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.

Cerium and cerium-based materials in dental applications / 中国组织工程研究

BACKGROUND:Cerium(Ce)is the most abundant element among lanthanides,which is mostly in the form of ceria.The reversible transformation between Ce3+and Ce4+ ions contributes to the high redox activity of cerium.Because of its antibacterial,anti-inflammatory,osteogenic,angiogenic and anti-tumor properties,cerium has been widely used in stomatology. OBJECTIVE:To summarize the antibacterial,anti-inflammatory,osteogenic,angiogenic and anti-tumor mechanism of cerium,and to review the research status and application prospects of cerium and cerium-based materials in the modification of oral materials and the diagnosis and treatment of oral diseases in recent years. METHODS:The articles published from database inception to 2023 were retrieved from Web of Science,PubMed,CNKI and WanFang databases with the search terms"cerium,ceria,prosthodontics,prosthesis,restorative dentistry,denture,dental implant,caries,endodontics,pulpitis,periodontitis,periodontal diseases,oral cancer"in English and"cerium,ceria,prosthodontics,implant,dental caries,dental pulp,periodontitis,periodontal disease,oral cancer"in Chinese.By analyzing and reading literature for screening,according to the inclusion and exclusion criteria,73 articles were finally included in this review. RESULTS AND CONCLUSION:(1)Cerium exerts an antibacterial effect through direct contact with bacteria,oxidative stress and destroying bacterial biofilm,and exerts an anti-inflammatory function based on mimetic enzyme activity.The osteogenic and angiogenic activities of cerium involve a series of signaling pathways including ERK and Wnt signaling pathways.(2)Antibacterial,anti-inflammatory,osteogenic,and angiogenic activities allow cerium significant potential in the treatment of oral infectious diseases and regeneration of oral soft and hard tissues.However,there is still a certain gap in the application of cerium's anti-tumor properties in the oral field.(3)Due to excellent mechanical properties and a low light-transmitting property,ceria-stabilized zirconia as a dental ceramic material can be used for core ceramics,the frameworks of dental prostheses and dental implants.(4)Benefited from its biological properties,cerium-based materials have the ability to promote osseointegration and soft tissue integration,inhibit demineralization and cariogenic bacteria,facilitate regeneration of the dentin-pulp complex,lessen inflammatory response and enhance periodontal tissue regeneration.There are wide applications of cerium in surface modifications of implants and treatments of caries,pulpitis,periodontitis and oral cancers.(5)Cerium shows certain toxicity under conditions of high concentration and long-term administration.To further expand clinical applications of cerium in dentistry,biosafety and optimization of cerium-based materials need to be further explored in the future.

Early Dental Failure and Medication-related Osteonecrosis of the Jaw in Patients Treated with Bisphosphonates:A Meta-analysis of Pro-portions / 医学研究杂志

Objective To assess the early dental failure rate and medication-related osteonecrosis of the jaw(MRONJ)incidence in patients treated with bisphosphonates(BPs),and provide evidence for evaluation of clinical risk.Methods Electronic databases,in-cluding Cochrane Library,Wiley Online Library,PubMed,CNKI and Wanfang Data were searched to collect clinical studies concerning early dental failure and medication-related osteonecrosis of the jaw in patients treated with bisphosphonates.The data were collected from inception until May 2022.The meta-analysis was conducted using Stata 15.Osoftware.Results A total of 13 clinical observational stud-ies involving 1261 implants,wherein 1182 implants were placed in patients who took bisphosphonate orally,and 79 implants were placed in patients treated with intravenous bisphosphonate.In patients who had orally administrated bisphosphonates,the pooled early dental fail-ure rate was 1.7％(95％CI:0.3％-3.9％),and the MRONJ incidence was 0.Among patients treated with intravenous bisphospho-nate,the pooled early dental failure rate was 0,and the MRONJ incidence was 5.6％.Conclusion The early dental failure rate and MRONJ incidence in patients who take bisphosphonates orally is as low as in a healthy population.On account of the relatively high risk of post-operative MRONJ in patients treated with intravenous bisphosphonates,clinical indications must be opted prudently.

A preliminary study on compliance of supportive treatment of patients with periodon-titis after implant restoration therapy / 北京大学学报(医学版)

Objective:To find out factors influencing the compliance of supportive treatment of patients with periodontitis who have received implant restoration therapy.Methods:Patients who had completed periodontal and implant restoration treatment for more than 5 years in Department of Periodontology,Pe-king University Hospital of Stomatology were subjected to inclusion between March 2022 and August 2023.A questionnaire was compiled to gather the information including patients'basic information(gen-der,age,and educational background etc.),smoking habits,general health conditions,oral hygiene habits,willingness to undertake periodontal and dental implant supportive treatment,actual fact on sup-portive treatment recorded in medical records,whether medical advices were correctly remembered,and reasons affected them to implement supportive therapy.The questionnaires were handed out to the above patients and filled during the process of follow-up treatment.Chi-square test,univariate and multivariate analysis of Logistic regression were employed to explore the correlations of these factors and the patients'compliance.Results:In the study,92 patients and questionnaires were collected and analyzed.The re-sults indicated that oral hygiene habits and whether medical advices were correctly remembered had sig-nificant correlation with compliance(P＜0.05).Time constraint(47.0％)and difficulty in appointment registration(24.8％)were the top 2 reasons obstructed them to undertake supportive treatment.Al-though the vast majority of the patients indicated willingness to perform follow-ups,55.4％of them wouldn't come back until the dentist called them back.The results of our study also indicated that the patients placed significantly less importance on the health of natural teeth than implants.Conclusion:In order to improve the compliance of supportive treatment,we suggest that dentists should put more empha-sis on oral hygiene instruction,and knowledge regarding periodontitis should also be added as part of pa-tient education contents.In the early stages of treatment,the patient should develop the habit of regular follow-up checks,More attention and patience should be given to elderly patients and those with lower level of education;use language that is easy to understand and printed medical instructions to help them remember.Patients can memorize better from refined doctors'advice,reinforcing care knowledge and refining medical advices can promote better follow-up treatment results.Motivating patients based on their characteristics is critical to improving compliance.

Trueness of different digital design methods for incisal guidance of maxillary anterior implant-supported single crowns / 北京大学学报(医学版)

Objective:To compare the trueness of incisal guidance of implant-supported single crowns designed by patient-specific motion(PSM)with that designed by average-value virtual articulator(AVA).Methods:The study had recruited 12 participants with complete dentition and stable incisal guidance.An intraoral scanner was used to scan digital casts and record two types of patient-specific mo-tion(data only including protrusive movement,and data including protrusive movement and lateral pro-trusive movement).The lingual surfaces of the maxillary incisors which guided the protrusive movement was selected and elevated to create a reference cast.A maxillary central incisor of original casts was vir-tually extracted and implanted to generate a working cast.The Dental system software program was used to design implant-supported single crowns with the anatomical coping design method.The incisal guidance was designed by different methods.The incisal guidance in control group was designed by the average-value virtual articulator.The incisal guidance in experiment groups was designed by the patient-specific motion only including protrusive movement(PSM1)and with the patient-specific motion including protru-sive movement and lateral protrusive movement(PSM2).The incisal guidance of prosthesis designed by these 3 methods were compared with the original incisal guidance in Geomagic Control 2015(3DSystem,America).The measurements included:Average of positive values,ratio of positive area and maximum value reflecting supra-occlusion;average of negative values,ratio of negative area and minimum value re-flecting over-correction;and root mean square reflecting overall deviation.Results:Statistical data were collected using the median(interquartile range)method.The average of positive values,ratio of positive area and average of negative values of the PSM2 group were smaller than those of the control group[8.0(18.8)μm vs.37.5(47.5)μm;0vs.7.2％(38.1％);-109.0(63.8)μm vs.-66.5(64.5)μm],and the ratio of negative area of PSM2 group was larger than those of the control group[52.9％(47.8％)vs.17.3％(45.3％)],with significant differences(P all＜0.05).The ratio of positive area[0.1％(7.0％)]and average of negative values[-97.0(61.5)μm]of PSM1 group,were smaller than those of the control group,and the ratio of negative area[40.7％(39.2％)]of the PSM1 group was larger than that of the control group,with significant differences(P＜0.05).The average of positive values[20.0(42.0)μm]and ratio of positive area of PSM1 group was larger than that of the PSM2 group with significant differences(P＜0.05).Conclusion:To establish the incisor guidance of implant-supported single crowns,compared with the average-value virtual articulator and the patient-specific motion only including protrusive movement,the patient-specific motion including protrusive movement and lateral protrusive movement is more conducive to reducing the protrusive interference of prosthesis and improving the occlusal fit.

Complexos polieletrólitos de quitosana e xantana carregados com ativos naturais e sintéticos: estudo físico/químico e microbiológico para aplicação de drug delivery / Polyelectrolyte complexes of chitosan and xanthan loaded with natural and synthetic actives: physicochemical and microbiological study for drug delivery application

A eficácia dos implantes osseointegrados é amplamente reconhecida na literatura científica. Contudo, infiltrações bacterianas na junção implante-pilar podem desencadear inflamação nos tecidos circundantes, contribuindo para a evolução de condições mais sérias, como a peri-implantite. O objetivo desse estudo foi produzir complexos polieletrólitos (PECs) de quitosana (Q) e xantana (X) em forma de membranas, carregá-las com ativos naturais e sintéticos antimicrobianos, caracterizálas estruturalmente e avaliá-las frente a degradação enzimática, cinética de liberação e ações antimicrobianas com finalidade de aplicação para drug delivery. Membranas de QX a 1% (m/v) foram produzidas em três proporções, totalizando doze grupos experimentais: QX (1:1); QX (1:2), QX (2:1), QX-P (com própolis) (1:1); QX-P (1:2); QX-P (2:1); QX-C (com canela) (1:1); QX-C (1:2); QX-C (2:1) e CLX (com clorexidina 0,2%) (1:1); CLX (1:2); CLX (2:1). Para os estudos de caracterização foram feitas análises da espessura em estado seco; análises morfológicas superficial e transversal em Microscopia Eletrônica de Varredura (MEV); análise estrutural de espectroscopia de infravermelho por transformada de Fourier (FTIR); análise de degradação por perda de massa sob ação da enzima lisozima; e análise da cinética de liberação dos ativos em saliva artificial. Para os testes microbiológicos, análises de verificação de halo de inibição e ação antibiofilme foram feitas contra cepas de Staphylococcus aureus (S. aureus) e Escherichia coli (E. coli). Os resultados demonstraram que a espessura das membranas variou conforme a proporção, sendo que o grupo QX (1:2) apresentou a maior média de 1,022 mm ± 0,2, seguida respectivamente do QX (1:1) com 0,641 mm ± 0,1 e QX (2:1) com 0,249 mm ± 0,1. Nas imagens de MEV é possível observar uma maior presença de fibras, rugosidade e porosidade nos grupos QX (1:2) e QX (1:1) respectivamente, e, no QX (2:1) uma superfície mais lisa, uniforme e fina. No FTIR foram confirmados os picos característicos dos materiais isoladamente, além de observar as ligações iônicas que ocorreram para formação dos PECs. Na análise de degradação, os grupos com ativos naturais adicionados tiveram melhores taxas de sobrevida do que os grupos QX. No teste de liberação, os grupos QX-P tiveram uma cinética mais lenta que os QX-C, cuja liberação acumulada de 100% foi feita em 24 h. Já nos testes do halo inibitório, somente os grupos CLX tiveram ação sobre as duas cepas, e os QX-P tiveram sobre S. aureus. Nas análises antibiofilme, os grupos CLX apresentaram as maiores taxas de redução metabólica nas duas cepas (± 79%); os grupos QX-P apresentaram taxas de redução similares em ambas as cepas, porém com percentual um pouco maior para E. coli (60- 80%) e os grupos QX-C tiveram grande discrepância entre as duas cepas: de 35 a 70% para S. aureus e 14 a 19% para E. coli. Pode-se concluir que, frente as análises feitas, o comportamento do material foi afetado diretamente pelos ativos adicionados a matriz polimérica. As proporções de Q ou X afetaram somente a espessura final. Quanto a aplicação proposta de drug delivery, os dispositivos apresentaram grande potencial, principalmente os grupos CLX e QX-P. (AU)

The effectiveness of osseointegrated implants is widely recognized in scientific literature. However, bacterial infiltrations at the implant-abutment interface may trigger inflammation in surrounding tissues, contributing to the development of more serious conditions, such as peri-implantitis. The aim of this study was to produce chitosan (Q) and xanthan (X) polyelectrolyte complexes (PECs) in the form of membranes, load and evaluate them for enzymatic degradation, release kinetics, and antimicrobial actions for drug delivery applications. QX membranes at 1% (w/v) were produced in three proportions, totaling twelve experimental groups: QX (1:1), QX (1:2), QX (2:1), QX-P (with propolis) (1:1), QX-P (1:2), QX-P (2:1), QX-C (with cinnamon) (1:1), QX-C (1:2), QX-C (2:1), and CLX (with 0.2% chlorhexidine) (1:1), CLX (1:2), CLX (2:1). Characterization studies included analyses of dry state thickness, surface and crosssectional morphology using Scanning Electron Microscopy (SEM), structural analysis by Fourier Transform Infrared (FTIR) spectroscopy, mass loss degradation analysis under lysozyme action, and active release kinetics analysis in artificial saliva. Microbiological tests included verification analyses of inhibition halos and antibiofilm action against strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Results showed that membrane thickness varied according to proportion, with group QX (1:2) presenting the highest average of 1.022 mm ± 0.2, followed by QX (1:1) with 0.641 mm ± 0.1, and QX (2:1) with 0.249 mm ± 0.1. SEM images showed greater presence of fibers, roughness, and porosity in groups QX (1:2) and QX (1:1) respectively, while QX (2:1) exhibited a smoother, more uniform, and thinner surface. FTIR confirmed characteristic peaks of the materials individually, besides showing ionic bonds formed for PECs. Degradation analysis revealed that groups with added natural actives had better survival rates than QX groups. In release tests, QX-P groups exhibited slower kinetics than QX-C, with 100% cumulative release achieved in 24 h. inhibitory halo tests, only CLX groups exhibited action against both strains, while QX-P acted against S. aureus. Antibiofilm analyses showed CLX groups with the highest metabolic reduction rates in both strains (± 79%); QX-P groups showed similar reduction rates in both strains, slightly higher for E. coli (60-80%), and QX-C groups had a significant discrepancy between strains: 35-70% for S. aureus and 14-19% for E. coli. In conclusion, material behavior was directly affected by added actives to the polymeric matrix. Proportions of Q or X only affected final thickness. Regarding proposed drug delivery applications, the devices showed great potential, especially CLX and QX-P groups.(AU)

Stress distribution in peri-implant bone, implants, and prostheses: 3D-FEA of marginal bone loss and prosthetic design / Distribuição de estresse no osso peri-implantar, implantes e próteses: análise 3D-FEA de perda óssea marginal e design protético

Objective: In response to the demand for dental implants, extensive research has been conducted on methods for transferring load to the surrounding bone. This study aimed to evaluate the stresses on the peripheral bone, implants, and prostheses under scenarios involving of the following variables: prosthesis designs, vertical bone heights, load angles, and restorative materials. Material and Methods: Three implants were inserted in the premolar and molar regions (5-6-7) of the two mandibular models. Model 1 represented 0 mm marginal bone loss and Model 2 simulated 3 mm bone loss. CAD/CAM-supported materials, hybrid ceramic (HC), resin-nano ceramic (RNC), lithium disilicate (LiSi), zirconia (Zr), and two prosthesis designs (splinted and non-splinted) were used for the implant-supported crowns. Forces were applied vertically (90°) to the central fossa and buccal cusps and obliquely (30°) to the buccal cusps only. The stresses were evaluated using a three-dimensional Finite Element Analysis. Results: Oblique loading resulted in the highest stress values. Of the four materials, RNC showed the low stress in the restoration, particularly in the marginal area. The use of different restorative materials did not affect stress distribution in the surrounding bone. The splinted prostheses generated lower stress magnitude on the bone, and while more stress on the implants were observed. Conclusion: In terms of the stress distribution on the peri-implant bone and implants, the use of different restorative materials is not important. Oblique loading resulted in higher stress values, and the splinted prosthesis design resulted in lower stress (AU)

Objetivo: Em resposta à demanda por implantes dentários, extensa pesquisa foi realizada sobre métodos para transferir carga ao osso circundante. Este estudo buscou avaliar os estresses no osso periférico, implantes e próteses em cenários que envolvem as seguintes variáveis: designs de próteses, alturas ósseas verticais, ângulos de carga e materiais restauradores. Material e Métodos: Três implantes foram inseridos nas regiões dos pré-molares e molares (5-6-7) de dois modelos de mandíbula. O Modelo 1 representou perda óssea marginal de 0 mm e o Modelo 2 simulou perda óssea de 3 mm. Materiais suportados por CAD/CAM, cerâmica híbrida (HC), cerâmica nano-resina (RNC), dissilicato de lítio (LiSi), zircônia (Zr) e dois designs de próteses (sintetizadas e não-sintetizadas) foram utilizados para as coroas suportadas por implantes. Forças foram aplicadas verticalmente (90°) à fossa central e cúspides bucais e obliquamente (30°) apenas às cúspides bucais. Os estresses foram avaliados usando Análise de Elementos Finitos tridimensional. Resultados: Cargas oblíquas resultaram nos valores mais altos de estresse. Entre os quatro materiais, RNC mostrou baixo estresse na restauração, especialmente na área marginal. O uso de diferentes materiais restauradores não afetou a distribuição de estresse no osso circundante. Próteses sintetizadas geraram menor magnitude de estresse no osso, enquanto mais estresse nos implantes foi observado. Conclusão: Em termos de distribuição de estresse no osso peri-implantar e implantes, o uso de diferentes materiais restauradores não é crucial. Cargas oblíquas resultaram em valores mais altos de estresse, e o design de prótese sintetizada resultou em menor estresse. (AU)

Análise mecânica comparativa do destorque de parafusos de minipilar com um novo componente protético, juntamente com avaliação microbiológica do vedamento para implantes de plataforma Cone Morse / Comparative mechanical analysis of the untorsion of miniabutment screws with a new prosthetic component, together with microbiological evaluation of the seal for Cone Morse platform implants

A interface implante pilar (IAI) por se constituir de duas peças inevitavelmente apresentam micro lacuna (GAP), na qual pode ocorrer infiltração bacteriana, permitindo a penetração de microorganismos que colonizam na parte interna do implante levando ao acúmulo de biofilme e, podendo levar ao desenvolvimento da periimplantite. O desgaste da conexão interna do implante é algo que ocorre com frequência, muitas vezes pela fratura do parafuso e/ou, pela perda da rosca interna do implante. A ausência de informações prévias também pode gerar a necessidade da remoção do implante, devido a estas intercorrências, surge a possibilidade da criação de um novo componente para implantes para possibilitar a reabilitação protética, sem ter que passar por uma nova cirurgia de remoção e instalação do implante. O objetivo do trabalho foi mensurar o nível de afrouxamento do parafuso do pilar protético e do minipilar comparando com novo componente protéticos, na tentativa de simular o comportamento do conjunto implante/pilar/prótese. Foram utilizados vinte implantes de plataforma cone morse (CM) da DSP® com seus respectivos mini pilares, na qual foram distribuídos em 2 grupos(n=10): Grupo 1 - implante CM + mini pilar FlexCone® DSP + coroa simplificada pirâmide invertida carga aplicada 3 mm do centro da coroa. E Grupo 2 - implante CM + mini pilar novo + coroa simplificada pirâmide invertida carga aplicada 3 mm do centro da coroa. Foram realizados ciclagem mecânica com carga 133 N, durante 2x106 ciclos, com frequência 2 Hz e temperatura de 37ºC em ambos grupos. Um torquímetro digital foi usado para medir os valores de torque reverso do parafuso protético da coroa e também do pilar protético, antes e após o carregamento. Os resultados do modelo de regressão demonstraram diferenças estatisticamente significativas em função do envelhecimento comparando os grupos da coroa sobre o pilar protético (p = 0.020) e entre os grupos do pilar sobre o implante (p = 0.048), indicando que após o envelhecimento de 2.000.000 de ciclos ao longo do tempo está associado de maneira significativa a essas variáveis no contexto deste estudo. O segundo objetivo deste estudo foi avaliar in vitro a taxa de infiltração bacteriana através da IAI, entre o novo componente protético e a superfície interna do implante, juntamente foi analisado a permeabilidade do IAI para colonização bacteriana. Um total de oitenta implantes foram testados. As estruturas montadas para grupo 1 foi torqueado com 20 N/cm e do G2 foram torqueados com 45 N, ambos imersos em microtubos contendo 200 µl de saliva humana. Após 14 dias de incubação da amostra de bactéria nos implantes, foi realizada uma análise qPCR (reação da cadeia da polimerase em tempo real). O teste revelou que não houve diferenças estatisticamente significativas no crescimento bacteriana entre os grupos em qualquer um dos pontos temporais analisados. Conclui-se que o novo componente testado apresentou um destoque menor do que comparado ao mini pilar FlexCone DSP® e apresentou infiltração bacteriana no GAP da conexão implante-pilar semelhante comparado ao mini pilar original da empresa (AU)

The abutment implant interface (IAI), as it consists of two pieces, inevitably presents a micro gap (GAP), in which bacterial infiltration can occur, allowing the penetration of microorganisms that colonize in the internal part of the implant, leading to the accumulation of biofilm and, which can lead to development of peri-implantitis. Wear of the implant's internal connection is something that occurs frequently, often due to screw fracture and/or loss of the implant's internal thread. The lack of prior information can also generate the need to remove the implant, due to these complications, the possibility arises of creating a new component for implants to enable prosthetic rehabilitation, without having to undergo a new surgery to remove and install the implant. implant. The objective of the work was to measure the level of screw loosening of the prosthetic abutment and the mini-abutment compared with the new prosthetic component, in an attempt to simulate the behavior of the implant/ abutment/prosthesis set. Twenty DSP® morse cone (CM) platform implants were used with their respective mini pillars, which were distributed into 2 groups (n=10): Group 1 - CM implant + FlexCone® DSP mini pillar + simplified crown inverted pyramid load applied 3 mm from the center of the crown. And Group 2 - CM implant + new mini abutment + simplified crown inverted pyramid load applied 3 mm from the center of the crown. Mechanical cycling was carried out with a load of 133 N, for 2x106 cycles, with a frequency of 2 Hz and a temperature of 37ºC in both groups. A digital torque wrench was used to measure the reverse torque values of the prosthetic crown screw and also the prosthetic abutment, before and after loading. The results of the regression model demonstrated statistically significant differences as a function of aging comparing the crown-on-prosthetic abutment groups (p =0.020) and between the abutment-on-implant groups (p = 0.048), indicating that after aging 2,000 ,000 cycles over time is significantly associated with these variables in the context of this study. The second objective of this study was to evaluate in vitro the rate of bacterial infiltration through the IAI, between the new prosthetic component and the internal surface of the implant, together with the permeability of the IAI for bacterial colonization. A total of eighty implants were tested. The assembled structures for group 1 were torqued with 20 N/cm and G2 were torqued with 45 N, both immersed in microtubes containing 200 µl of human saliva. After 14 days of incubation of the bacteria sample in the implants, a qPCR (real-time polymerase chain reaction) analysis was performed. The test revealed that there were no statistically significant differences in bacterial growth between groups at any of the time points analyzed. It is concluded that the new component tested presented a lower impact compared to the FlexCone DSP® mini abutment and presented bacterial infiltration in the GAP of the implant-abutment connection similar to the company's original mini abutment.(AU)

Corrección del artefacto producido en imágenes tomográficas en equipos odontológicos / Correction of the artifact produced in tomographic images in dental equipment

Objetivo: disminuir el efecto de artefacto que generan objetos de alta densidad mediante la utilización de filtros de distintos materiales y espesores, ubicados en lugares estratégicos del tomógrafo. Material y métodos: se utilizaron filtros de aluminio y de cobre ubicados en lugares estratégicos en el equipo tomográfico. Se realizaron cortes oblicuos en piezas dentarias con restauraciones metálicas y en implantes; se midió la extensión del artefacto en ancho y alto en cada adquisición tomográfica. Resultados: se hallaron diferencias significativas respecto a la disminución de la dispersión de acuerdo con cada filtro con respecto a la no utilización de estos elementos. Conclusión: la utilización de filtros logró disminuir el efecto de artefacto en estructuras de alta densidad, obteniendo una mejor calidad de imagen para el diagnóstico, permitiendo que el software pueda reconstruir una imagen real (AU)

Objective: to diminish the artifact effect generated by high density objects by using filters of different materials and thickness, located in strategic places of the tomograph. Material and methods: aluminum and copper filters located in strategic places in the tomographic equipment were used. Oblique cuts were made on dental pieces with metal restorations and implants; the extension of the artifact in width and height was measured in each tomographic acquisition. Results: significant differences were found regarding the decrease of the dispersion according to each filter with respect to the non-use of these elements. Conclusion: the use of filters achieves to diminish the artifact effect in structures of high density, obtaining a better image quality for the diagnosis, allowing the software to reconstruct a real image (AU)

Synthetic Hydroxyapatite Bone Graft Substitute In Sinus Augmentation - A Histological Analysis

Aim: Material And Method:To see the effect of synthetic Hydroxyapatite bone graft substitute in sinus augmentation. A lateral window was cut on the buccal aspect of the maxilla on the posterior region in the area of molar I/II and after carefully lifting the sinus membrane, bone graft was packed and a collagen membrane was placed on top of it. After a period of 8 months the site was re-entered to take bone sample for histological analysis using a trephine, at the same time, implant (Bioner Top DM, 4/10) was placed at the surgical site. The surgical site healed well. G-Bone hasResults: shown good bone growth histologically. The surgical site healed well. G-Bone has shown good bone growthConclusion: histologically.

Protocolo Abreviado Guiado Digital: Técnicas de Marcadores Tisulares, Silicona de Registro y CBCT con Sonrisa / Digitally Guided Abbreviated Protocol: Tissue Marker Techniques, Recording Silicone and CBCT with Smile

Establecer un protocolo de cirugía guiada estática con técnicas referenciales para ser realizado de manera predecible, repetible y simple, en todos los tipos de casos. El protocolo abreviado guiado digital para cirugía guiada estática para implantes se centra en diseñar computacionalmente una guía quirúrgica que se apoye en el tejido remanente del paciente, siendo un protocolo digital versátil para la cirugía y rehabilitación implanto protésica, basada en registros clínicos, principalmente la línea de la sonrisa y la captación de ésta en tomografía de haz cónico (CBCT), además de establecer dimensión vertical oclusal (DVO). Logrando así, planificación de implantes hasta la inserción inmediata de la prótesis temporal. Se ejemplifica el trabajo con 2 casos clínicos. Se establece un protocolo con la intención de que pueda ser realizado en pacientes desdentados parciales (Técnica de Registro Silicona) o totales (Técnica de Marcadores Tisulares en prótesis), definiendo un flujo de trabajo tridimensional, digital y optimizado, con un consecuente ahorro de tiempo clínico. Como principio del protocolo de cirugía guiada es lograr el objetivo quirúrgico - protésico deseado con alta precisión. La cirugía y rehabilitación de implantes de manera convencional es altamente dependiente del operador por lo que la alternativa de cirugía guiada de manera estática es una herramienta más para mejorar el pronóstico del paciente. Se establece un protocolo digital simple y efectivo, de cirugía guiada, para la rehabilitación implanto protésica basada en la línea de la sonrisa, tomografía de haz cónico (CBCT), dimensión vertical oclusal (DVO). Protocolo predecible y que optimiza los tiempos clínicos, logrando una rehabilitación protésica inmediata acorde e individualizada para cada paciente.

Establish a static guided surgery protocol with referential techniques to be performed in a predictable, repeatable and simple way, in all types of cases. The abbreviated digital guided protocol for static guided surgery for implants focuses on computationally designing a surgical guide that rests on the patient's remaining tissue, being a versatile digital protocol for prosthetic implant surgery and rehabilitation, based on clinical records, mainly the line of the smile and its uptake in cone beam tomography (CBCT), in addition to establishing occlusal vertical dimension (OVD). Thus achieving implant planning until the immediate insertion of the temporary prosthesis. The work is exemplified with 2 clinical cases. A protocol is established with the intention that it can be carried out in partially edentulous patients (Silicone Registration Technique) or total (Tissue Marker Technique in prostheses), defining a three-dimensional, digital and optimized workflow, with a consequent saving of time. clinical. As a principle of the guided surgery protocol, it is to achieve the desired surgical-prosthetic objective with high precision. Conventional implant surgery and rehabilitation is highly dependent on the operator, so the alternative of statically guided surgery is one more tool to improve the patient's prognosis. A simple and effective digital protocol for guided surgery is established for prosthetic implant rehabilitation based on the smile line, cone beam tomography (CBCT), and occlusal vertical dimension (OVD). Predictable protocol that optimizes clinical times, achieving an immediate and individualized prosthetic rehabilitation for each patient.

Cirurgia guiada em implantodontia: revisão integrativa / Guided surgery in implantodogy: integrative review

A cirurgia guiada estática se caracteriza por utilizar de um guia cirúrgico que tem como objetivo reproduzir a posição virtual ideal do implante, por meio de sítios criados para a inserção de uma série de brocas de acordo com a trajetória pré estabelecida pelo planejamento digital. Realizar uma revisão integrativa da literatura sobre cirurgia guiada estática em implantodontia, demonstrando sua importância, vantagens, desvantagens, limitações e complicações em comparação com técnica convencional. Tratou-se de uma revisão integrativa da literatura de natureza exploratória, realizada durante o período de agosto de 2021 e maio de 2022, a partir das produções científicas indexadas na base eletrônica da PubMed. Um total de 13 estudos foram incluídos após a seleção e suas evidências foram reunidas para esclarecer os objetos propostos. Os estudos demostraram que uma das principais vantagens da técnica guiada estática é a precisão em relação a técnica convencional e melhor pós operatório de dor relatado pelos pacientes. Não se pode confiar totalmente no processo de produção dos guias, devido o fator experiencia está associado, além que o custo e tempo dessa produção são elevados. Como complicação e limitação os estudos citam possibilidades de ocorrer mínimo acesso ao sítio cirúrgico e fratura do guia. A cirurgia guiada é uma excelente alternativa, as vantagens mais citadas são em relação a precisão, redução da dor, no entanto há fatores negativos como custo, a impossibilidade de mudança no transoperatório e possíveis erros de fabricação. Existem ainda limitações como fratura da guia e baixo acesso ao sítio cirúrgico.

Static guided surgery is characterized by using a surgical guide that aims to reproduce the ideal virtual position of the implant, through sites created for the insertion of a series of drills according to the trajectory pre-established by digital planning. Perform an integrative review of the literature on static guided surgery in implantodontia, demonstrating its importance, advantages, disadvantages, limitations and complications compared to conventional technique. This was an integrative review of the exploratory literature, carried out during the period of August 2021 and May 2022, from the scientific productions indexed in pubmed's electronic database. A total of 13 studies were included after selection and their evidence was gathered to clarify the proposed objects. Studies have shown that one of the main advantages of the static guided technique is accuracy in relation to the conventional technique and better postoperative pain reported by patients. One cannot fully trust the production process of the guides, due to the experience factor is associated, and the cost and time of this production are high. As a complication and limitation, studies mention possibilities of minimal access to the surgical site and fracture of the guide. Guided surgery is an excellent alternative, the most cited advantages are in relation to accuracy, pain reduction, however there are negative factors such as cost, the impossibility of change in the transoperative period and possible manufacturing errors. There are also limitations such as fracture of the guide and low access to the surgical site.

Regulación de la implantología dental en México / Regulation of dental implantology in Mexico

Introducción: los implantes dentales se han convertido en uno de los tratamientos odontológicos con mayor demanda en todo el mundo, no sólo por el nivel máximo de funcionalidad y de estética, sino también debido a su estabilidad, osteointegración y facilidad en su rehabilitación. Es incierto si los implantes dentales se encuentran normados formalmente en México, lo que motiva a la revisión del estado actual. Objetivo: evidenciar el estado actual de la legislación de la práctica de la implantología dental en México a través de una revisión en la literatura. Material y métodos: revisión de las legislaciones existentes en México para la aplicación de implantes dentales y su contraparte en el mundo a través de la evaluación de normas expedidas en América y Europa. Resultados: se contabilizó un total de 17 escuelas de implantes dentales que cuentan con el reconocimiento de la Secretaría de Educación Pública, de las cuales tres son públicas y 14 privadas. Se presentó una discrepancia en los planes de estudio que va de 16 a 36 meses. Las escuelas no contaron con un aval normativo. Las normas internacionales para control de calidad y aplicación de la tecnología en implantes se ubicaron en Canadá, Estados Unidos, España, Reino Unido y Francia. Conclusiones: contar con un antecedente normativo establecido por los países de primer mundo y ausente en México permite evidenciar la necesidad de implementar una Norma Oficial Mexicana que regule la fabricación, distribución y almacenamiento de los implantes dentales en México. A la vez, la revisión sugiere que la Secretaría de Educación Pública norme los créditos mínimos necesarios en las instituciones educativas reconocidas para la formación de recursos humanos que ejercen la implantología dental (AU)

Introduction: dental implants have become one of the dental treatments with the highest demand in the world, not only because of the highest level of functionality and aesthetics, but also because of their stability, osseointegration and ease of rehabilitation. It is uncertain if dental implants are formally regulated in Mexico, which motivates the review of the current status. Objective: to demonstrate the current state of the legislation for the practice of dental implantology in Mexico through a review of the literature. Material and methods: review of the existing legislation in Mexico, for the application of dental implants and its counterpart in the world, through the evaluation of standards issued in America and Europe. Results: a total of 17 dental implant schools that have the recognition of the Ministry of Public Education were counted, of which 3 are public and 14 private. There was a discrepancy in the study plans that ranged from 16 to 36 months. Schools will not have regulatory backing. The international standards for quality control and application of technology in implants were located in Canada, the United States, Spain, the United Kingdom and France. Conclusions: having a normative antecedent established by the countries of the first world and absent in Mexico, allows to demonstrate the need for the implementation of an Official Mexican Standard, which regulates the manufacture, distribution and storage of dental implants in Mexico. At the same time, the review suggests that the Ministry of Public Education regulate the minimum necessary credits in recognized educational institutions, for the training of human resources that practice dental implantology (AU)

Evaluation of the occlusal contact area of molar dental implants comparing two different thicknesses (16 µm and 200 µm) of articulating occlusal papers and forces (200 and 250 N): a pivot in vitro study

Introduction: The goal of this pilot study was to evaluate the differences between checking occlusion on implants crowns using 16 or 200 µm thickness of articulating occlusal paper, and to compare the stained occlusal area between the groups after bite forces of 200 and 250 N. Methods: It was included 10 casts of articulated-type IV gypsum, 10 NiCr crowns, articulating occlusal papers (16 µm and 200 µm thick), and a compression test machine. Compressive forces (200 and 250 N.mm) were applied on models, to check the occlusal contact area of fixed and cemented crowns. The contact areas on the crowns were measured through images obtained by the scanning electron microscope. Statistical tests were performed considering the significant level of 5% (p≤0.05). Results: The stains found using 200 µm of articulating paper were higher than those with 16 µm, independent of the force applied. However, the stains obtained in lower teeth with different strengths (200 and 250N) marked with 16 µm articulating paper were not possible to score. The articulating paper variable had significant statistical results (p=0.002), while the variables force (p=0.443) and articulating paper-force interaction (p=0.607) were not significant. The mean area found in staining using the 200 µm and 16 µm papers was, respectively, 8.3380 mm2 and 3.4759 mm2. Conclusion: It was possible to confirm that 200 µm of articulating occlusal paper showed better and significant results to stain the occlusal area, permitting a more accurate adjustment independent of the force applied.

Multi-disciplinary treatment of severe palatal radicular groove of maxillary lateral incisor: A case report and literature review / 中南大学学报(医学版)

Palatal radicular groove is a developmental malformation of maxillary incisors, lateral incisors in particular, which often causes periodontal destruction. This paper reports a case of combined periodontal-endodontic lesions induced by palatal radicular groove, which was initially misdiagnosed as a simple periapical cyst. After root canal therapy and periapical cyst curettage, the course of disease was prolonged, resulting in the absence of buccal and maxillary bone plates in the affected tooth area. After the etiology was determined, the affected tooth was extracted and guide bone tissue regeneration was performed at the same time, followed by implantation and restoration at the later stage, leading to clinical cure. The palatal radicular groove is highly occult, and the clinical symptoms are not typical. If the abscess of the maxillary lateral incisor occurs repeatedly, and the abscess of the maxillary lateral incisor has not been cured after periodontal and root canal treatment, cone-beam computed tomographic and periodontal flap surgery should be considered.

Measurement and analysis of implant-related anatomical structure in the adult mandibular posterior tooth area based on CBCT / 安徽医科大学学报

Objective @#To measure and analyze the position and shape of implant-related anatomical structure such as mental foramen，mental canal and the submandibular fossa in the adult mandibular posterior tooth area based on Cone Beam Computed Tomography( CBCT) images，and to detect the relationship between anatomical structures and the anatomice buccalingual angulation at implant site in order to help determine the implant angulation at the implant treatment-planning phase．@*Methods@#Random samples of 181 CBCT images were selected and analyzed，including 109 patients with dentition defect : 59 males and 50 females，and 72 patients with non dentition defect : 36 males and 36 females．The anatomic marks and alveolar bone inclination of mandibular posterior tooth area were measured respectively，and the results were statistically analyzed. @*Results @#The inclination angles of alveolar bone were (5. 08 ± 3. 86) on the left and (3. 07 ± 5. 20) on the right of the mental foramen area，(8. 57 ± 5. 03) and (9. 54 ± 5. 19) on the first mandibular molar，( 15. 48 ± 5. 23) and ( 14. 21 ± 6. 67) on the second mandibular molar，and the inclination angles of the left and right mental canal were (41. 81 ± 10. 07) and (44. 77 ± 8. 96) respectively．The distance from the upper edge of the mental foramen to the top of the alveolar ridge was ( 12. 35 ± 2. 38) mm，and the distance between the mental canal at 1．5 mm inside the mental foramen and the top of the alveolar ridge was ( 14. 14 ± 2. 46) mm．The depth of the submandibular gland fossa in the first and second molars were (0. 80 ± 0. 56) mm and ( 1. 00 ± 0. 50) mm，the distance from the most concave point to the alveolar crest top were ( 14. 15 ± 5. 95) mm and ( 14. 52 ± 3. 55) mm，the distance from the most convex point of the crown to the alveolar crest top were ( 10. 71 ± 4. 72) mm and (9. 25 ± 2. 81) mm，and the distance from the upper edge of the mandibular canal to the alveolar crest top were ( 15. 52 ± 3. 48) mm and ( 13. 83 ± 2. 76) mm．@*Conclusion@#The buccallingual inclination of mandibular alveolar bone is gradually inclined from buccal side to lingual side from premolar area to molar area，and the lingual inclination in the second molar area is the most obvious ; The implant tip can stop at the upper edge of the mental foramen to obtain better initial stability ; The existence of submandibular fossa limits the depth and direction of implant implantation to a certain extent．It is necessary to accurately measure and analyze this part with CBCT before operation to avoid complications such as mandibular lingual perforation and improve the success rate of implant repair.

Accuracy of selective laser sintered computer guided stents versus digital light processing stents in immediate implant placement in esthetic zone: a randomized controlled trial / Precisão de stents sinterizados por laser seletivo guiados por computador versus stents de processamento de luz digital na colocação imediata de implantes em região estética: um ensaio randomizado

Objective: To compare accuracy of selective laser sintered computer guided stents versus digital light processing stents in immediate implant placement in esthetic zone. Material and Methods: The patients were selected according to the eligibility criterias. The selected patients were randomly allocated to either digital light processing stents (test group) or selective laser sintered computer guided stents (control group). Proper examination and diagnostic records were done for each patient followed by triple scan protocol with cone beam computer tomography (CBCT). Planning and construction of tooth supported computer guided surgical stent was done by either digital light processing technique for test group or selective laser sintering for control group. Twenty implants were inserted following computer guided implant placement protocol. After post-operative CBCT pre and post images were merged using blue sky bio software. Linear and angular deviations between planned implant and actual implant positions were measured. Results: Tests were considered statistically significant if the p- value was less than 0.05. Difference in means were calculated for the analysis of continuous variables with corresponding 95% confidence intervals. There was no statistical difference between selective laser sintering and digital light processing groups in all measured terms. Conclusion : Within the limitations of this study, both techniques can be used for immediate implant placement with clinically satisfactory results decreasing the positional errors associated with immediate implant placement. (AU)

Objetivo: Comparar a acurácia de stents sinterizados por laser seletivo guiados por computador versus stents de processamento de luz digital na colocação imediata de implantes em região estética. Material e Métodos: Os pacientes foram selecionados de acordo com os critérios de elegibilidade. Os pacientes selecionados foram distribuídos aleatoriamente nos seguintes grupos: stents de processamento de luz digital (grupo experimental) ou stents sinterizados por laser seletivo guiados por computador (grupo controle). Os registros dos exames adequados e diagnósticos foram realizados para cada paciente seguido por um protocolo de varredura tripla com tomografia computadorizada de feixe cônico (TCFC).O planejamento e a construção do Stent cirúrgico guiado por computador com suporte dentário foram feitos pela técnica de processamento de luz digital para o grupo experimental ou sinterização a laser seletivo para o grupo controle. Vinte implantes foram inseridos seguindo o protocolo de colocação de implante guiado por computador. Após a TCFC pós-operatória, as imagens pré e pós foram mescladas usando o software blue sky bio. Foram medidos os desvios lineares e angulares entre o implante planejado e as posições reais do implante. Resultados: Os testes foram considerados estatisticamente significativos se o valor de p fosse menor que 0,05. A diferença nas médias foi calculada para a análise das variáveis contínuas com intervalos de confiança de 95%. Não houve diferença estatística entre os grupos de sinterização a laser seletivo e processamento digital de luz em todos as variáveis mensuradas. Conclusão: Dentro das limitações deste estudo, ambas as técnicas podem ser utilizadas para colocação imediata de implantes com resultados clinicamente satisfatórios diminuindo os erros posicionais associados colocação imediata de implantes. (AU)

Progress of research on bone grafts for implant dentistry / 口腔医学

@#With the development of dental implant techniques, dental rehabilitation of partially or totally edentulous patients with oral implants has become a common practice. Adequate bone volume in the implant area is a key factor for the success of implant restoration. However, insufficient bone volume in the implant area is very common in clinical practice, which jeopardizes the structural, functional, and esthetic outcomes of implant treatment. Bone augmentation with bone grafts is one of the methods commonly used in clinical practice to meet the requirements of implantation. Properties of bone grafts, such as biocompatibility,osteoconduction, osteoinduction and osteogenesis, are important to the success of bone augmentation. This paper reviews current research on dental bone grafts about their clinically relevant capabilities, classification and their potential development in the future, in order to provide theoretical reference for clinical application of bone grafts and successful implant restoration.

Dental implant treatment in vascularized bone flaps after jaw reconstruction / 华西口腔医学杂志

Jaw defects caused by various reasons often seriously affect appearance and function. The goal of the treatment of oral and maxillofacial tumors should include the cure of the tumor and the restoration of premorbid function. The development of microsurgery and digital surgery technology has promoted the development of jaw reconstruction with vascularized free bone flap. Good appearance and improved predictability could be obtained with the help of preope-rative visual design. How to rehabilitate occlusal function on the reconstructed jaw and improve the quality of life of patients has become an important research direction. This article discusses the challenge of jaw reconstruction, the selection of vascularized bone flap, the choice of implant timing, the treatment of peri-implant soft tissue, and the influence of radiotherapy on implants after jaw reconstruction.