Biomechanical behavior of three maxillary expanders in cleft lip and palate: a finite element study.

This study evaluated the stress distribution in the dentoalveolar and palatal bone structures during maxillary expansion in a 17-year-old male patient with bilateral cleft lip and palate (BCLP) using expanders with dental (HYRAX) and skeletal anchorage (MARPE). For the generation of the specific finite element models, cone-beam computed tomography was used, and the DICOM files were exported to Mimics 3-Matic (Materialise) and Patran (MSC Software) software. Three specific three-dimensional models were generated: A) HYRAX: conventional four-banded hyrax screw (9 mm); B) MARPE-DS: 3 miniscrews (1.8 mm diameter - 5.4 mm length) and four-banded dental anchorage; and C) MARPE-NoDS: 3 miniscrews without dental anchorage. Maxillary expansion was simulated by activating the expanders transversely 1 mm on the "X" axis. HYRAX resulted in higher levels of deformation predominantly in the dentoalveolar region. MARPE-DS showed stress in the dentoalveolar region and mainly in the center of the palatal region, at approximately 4,000 µÎµ. MARPE-NoDS exhibited evident stress only in the palatal region. High stress levels in the root anchoring teeth were observed for HYRAX and MARPE-DS. In contrast, MARPE-NoDS cause stress on the tooth structure. The stress distribution from the expanders used in the BLCP showed asymmetric expansive behavior. During the initial activation phase of expansion, the HYRAX and MARPE-DS models produced similarly high strain at the dentoalveolar structures and upper posterior teeth displacement. The MARPE-NoDS model showed restricted strain on the palate.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction.

This study evaluates the effects of a green tea (Camellia sinensis) and hyaluronic acid gel on fibroblast activity and alveolar bone repair following third molar extractions. By examining the gene expression related to cell survival, proliferation, and angiogenesis, the study bridges in vitro findings with clinical outcomes in a split-mouth randomized trial. Human fibroblasts were exposed to the treatment gel, analysing gene expression through RT-qPCR. Twenty participants undergoing bilateral third molar extractions received the test gel on one side and a placebo on the other. Assessments included patient-reported outcomes, professional evaluations, and radiographic analyses at multiple postoperative intervals. The test gel significantly enhanced AKT, CDKs, and VEGF gene expressions, indicating a positive effect on angiogenesis and cell proliferation. Clinically, it resulted in reduced exudate, swelling, and secondary interventions, with radiographs showing improved alveolar bone density after 90 days. The green tea and hyaluronic acid gel significantly improves soft tissue and bone healing post-extraction, offering a promising adjunctive therapy for enhancing postoperative recovery. This gel represents a novel adjuvant treatment option for facilitating improved healing outcomes after third molar extractions, highlighting its potential utility in clinical dental practice.

Effect of the association of infra-red and red wavelength photobiomodulation therapy on the healing of post-extraction sockets of third lower molars: a split-mouth randomized clinical trial.

The aim of this study was to evaluate the effect of photobiomodulation therapy (PBMT) with the association of red and infra-red laser therapy in the healing of the post-extraction sockets of third lower molars. Twenty patients were submitted to extraction of lower third molars and the post-extraction sockets were treated using two different approaches in a randomized split-mouth design: The test side received the PBMT with red (λ 660 nm) and infra-red laser therapy (λ 808 nm) and the control side was not irradiated. The PBMT was applied immediately and 3 and 7 days after the surgical procedure. Post-extraction socket healing was assessed by the bone repair score, bone density, and fractal dimension analysis 7 and 90 days after the surgical procedure, using cone-beam computed tomography images. Additionally, clinical analyses were performed 3, 7, 14, 30, and 90 days after the surgical procedure, considering the occurrence of pain, edema, and bleeding, as well as the quality of the oral mucosa repair, assessed using a visual analogue scale. The clinical analysis showed that PBMT reduced edema and improved the repair of oral mucosa at 7 days after surgery, while the tomographic analysis showed no significant differences between groups. Dual-wavelength PBMT improved the post-operative clinical course in patients undergoing lower third molar extraction, without altering bone repair.

Biomechanical Effect of Ferrule on Incisors Restored with a Fiberglass Post and Lithium-Disilicate Ceramic Crown after Thermal Cycling and Fatigue Loading.

PURPOSE: To evaluate the biomechanics of endodontically treated incisors restored with a fiberglass post and a CAD/CAM lithium-disilicate ceramic crown with/without a ferrule after thermal and mechanical aging. MATERIALS AND METHODS: Twenty bovine incisors were divided into two groups (n = 10): 1. Fe, with a ferrule of 2 mm, and 2. NFe, without a ferrule. After endodontic treatment, the teeth were restored using a fiberglass post (Exacto 3, Angelus) and composite core (Tetric Ceram, Ivoclar Vivadent). They then received a CAD/CAM lithium-disilicate ceramic crown (IPS e.max CAD) luted using a self-adhesive composite (RelyX Unicem 2, 3M Oral Care). All specimens were subjected to 20,000 thermocycles and 2,400,000 simulated chewing cycles. Ceramic crown and root dentin strains (µS) were measured using strain gauges (n = 10) during 100-N loading before and after the thermal and mechanical aging, and upon fracture loading. The specimens were subsequently loaded to fracture (N). The stress distribution was analyzed using 3D individualized finite-element models created by micro-CT of experimental samples (n = 3). Strain data were analyzed using two-way ANOVA and Tukey's HSD test. Fracture resistance was analyzed using Student's t-test and fracture mode was analyzed using the chi-squared test (α = 0.05). RESULTS: After aging, NFe exhibited significantly higher root dentin deformation (buccal: 1248.0 ± 282.8; lingual: 516.2 ± 195.0; p < 0.001) than Fe (buccal, 554.0 ± 233.8; lingual: 311.8 ± 159.0; p < 0.001). The deformation measured on ceramic crowns was not influenced by ferrule presence or aging process. Significantly higher fracture resistance (N) was observed for the Fe (1099.6 ± 214.8) than the NFe group (675.3 ± 113.8) (p < 0.001). The NFe group revealed a lower fracture resistance:root strain ratio than did the Fe group. The stress levels on root dentin and fiberglass were lower for the Fe group. CONCLUSION: The NFe group showed increased root dentin strain after the aging process. The Fe group revealed higher fracture resistance, lower stress concentration on root dentin and fewer catastrophic fractures.

Patient-specific Finite Element Analysis of Fiber Post and Ferrule Design.

INTRODUCTION: A ferrule on anterior endodontic-treated teeth has been evaluated using clinical trials, in vitro tests, and finite element analysis (FEA). The patient-specific FEA with a nonuniform ferrule and nonlinear contact biting load associated with clinical validation can be used to predict failure. METHODS: A patient was selected with both maxillary central incisors with different ferrule designs who received endodontic treatment and restoration using a fiber post, composite core, and computer aided design and computer aided manufacturing lithium disilicate ceramic crowns. Strain gauges were attached to the buccal surfaces of both teeth to record ceramic strain during bite force recording for FEA validation. Cone-beam computed tomographic imaging was performed, and the Digital Imaging and Communication in Medicine files were exported to Mimics, 3-Matic (Materialise, Leuven, Belgium) and Patran (MSC Software, Santa Ana, CA) software to create a patient-specific FEA model. Bite load was applied using contact load applied by antagonist teeth (155 N). Mechanical properties were obtained from the literature. Modified von Mises equivalent stress was used for stress evaluation. RESULTS: Stresses on the dentin and fiber post on the left incisor, which had a nonuniform ferrule, were higher compared with the right incisor. The strain values recorded for the right central incisor (strain gauge =79.9 ± 3.8 µS and FEA = 69.5 µS) and the left central incisor (strain gauge = 83.5 ± 5.3 µS and FEA = 73.9 µS) validate the FEA analysis. CONCLUSIONS: FEA was validated with in vivo strain values measured at the buccal crown surfaces, supporting that the stress levels were realistic for investigation of the clinical performance of fiber posts. Maintaining a uniform ferrule was more favorable than a localized higher ferrule.

A conservative approach to retrieve a fractured abutment screw - Case report.

INTRODUCTION: Regarding implant-supported prostheses, the most reported types of complications are related to loosening or fracturing of abutment or prosthesis screws. This case report shows a series of procedures that allowed a conservative solution for a fractured screw. It avoided removing the implant and also allowed the same prosthesis to be used after guided-drilling the fractured screw and re-tapping the implant internal threads. The same prosthesis was replaced immediately after the procedure. PATIENT: A 67-year-old male patient, who had a fractured abutment screw of the lower left first molar implant. The patient decided for the conservative treatment option and an attempt was made to remove the fractured screw. DISCUSSION: Parafunctional habits can generate excessive occlusal forces, which are risk factors associated with loosening and fracturing implant screws and even the fixtures themselves. This case report focus on the probable causes, difficulties and risks associated with this procedure and it also discusses the alternative approaches. CONCLUSION: The purposed treatment allowed a time and money saving resolution for fractured abutment screws.

Avaliação do impacto do edentulismo total mandibular e da reabilitação fixa sobre implantes com carga imediata na qualidade de vida de pacientes idosos / The impact of the mandibular edentulism and the oral rehabilitation with immediate loading fixed prosthesis in the quality of life of elderly patients

O objetivo deste estudo foi avaliar o impacto da reabilitação bucal com próteses fixas suportadas por implantes em pacientes edêntulos totais mandibulares. A amostra foi formada por doze pacientes do Instituto Nacional de Experimentos e Pesquisas Odontológicas (INEPO, São Paulo, Brasil), com média de idade de 59 anos, que se submeteram a cirurgia para instalação de quatro implantes na região mandibular seguida pela instalação de prótese fixa em protocolo de carga imediata funcional. Os pacientes responderam a um questionário contendo quatorze perguntas objetivas de múltipla escolha (OHIP-14 - Oral Health Impact Profile) em duas ocasiões: previamente à cirurgia de implantes e seis meses após a instalação da reabilitação protética. A análise estatística dos dados obtidos demonstrou que a qualidade de vida dos pacientes melhorou significativamente (P = 0,001) após a substituição da prótese total removível pela prótese fixa sobre implantes.

The aim of this study was to evaluate the impact of oral rehabilitation with fixed implant prosthesis in the quality of life of edentulous patients, The sample consisted of twelve patients from the National Institute of Dental Research and Experiments (INEPO, São Paulo, Brazil) with a mean age of 59 years who underwent surgery to install four implants in the lower jaw followed by fixed prosthesis with immediate functional loading. The patients answered a questionnaire containing fourteen multiple choice objective questions (OHIP-14 - Oral Health Impact Profile) on two occasions: first before the implant surgery, and then six months after the treatment with implant supported fixed prosthesis. Statistical analysis of data obtained demonstrated that the patients' quality of life improved significantly (P = 0,001) after the replacement of removable dentures by implant-supported fixed prosthesis.

Influence of clinically relevant factors on the immediate biomechanical surrounding for a series of dental implant designs.

The objective of the present study was to assess the influence of various clinically relevant scenarios on the strain distribution in the biomechanical surrounding of five different dental implant macrogeometries. The biomechanical environment surrounding an implant, i.e., the cortical and trabecular bone, was modeled along with the implant. These models included two different values of the study parameters including loading conditions, trabecular bone elastic modulus, cortical/trabecular bone thickness ratio, and bone loss for five implant designs. Finite element analysis was conducted on the models and strain in the bones surrounding the implant was calculated. Bone volumes having strains in four different windows of 0-200 µÎµ, 200-1000 µÎµ, 1000-3000 µÎµ, and > 3000 µÎµ were measured and the effect of each biomechanical variable and their two-way interactions were statistically analyzed using the analysis of variance method. This study showed that all the parameters included in this study had an effect on the volume of bones in all strain windows, except the implant design, which affected only the 0-200 µÎµ and >3000 µÎµ windows. The two-way interaction results showed that interactions existed between implant design and bone loss, and loading condition, bone loss in the 200-1000 µÎµ window, and between implant design and loading condition in the 0-200 µÎµ window. Within the limitations of the present methodology, it can be concluded that although some unfavorable clinical scenarios demonstrated a higher volume of bone in deleterious strain levels, a tendency toward the biomechanical equilibrium was evidenced regardless of the implant design.

Estudo clínico prospectivo longitudinal não interferencial avaliando implantes com tratamento de superfície e câmara de cicatrização / A non interferencial longitudinal prospective study evaluating dental implants with treated surface and healing chambers

O uso de implantes osseointegráveis no tratamento do edentulismo é hoje uma das técnicas mais previsíveis e bem sucedidas no âmbito da odontologia contemporânea. Entretanto o protocolo mais utilizado para utilização destes implantes requer um período de osseointegração de alguns meses antes que a restauração protética seja efetivamente instalada. Muitas vezes, até mesmo de maneira empírica, para se diminuir este tempo de espera o protocolo original é alterado, diminuindo-se o período de osseointegração. O objetivo deste trabalho é apresentar de maneira sucinta o estágio atual de aprimoramento dos implantes dentários para aperfeiçoar o processo de osseointegração, com relação às alterações de superfície e da forma destes dispositivos, além de apresentar os resultados clínicos obtidos com a instalação de 603 implantes com tratamento de superfície por duplo ataque ácido e câmara de cicatrização.

The use of osseointegrated implants in the handling of the edentulism is today one of the most foreseeable techniques and well happened in the scope of the contemporary dentistry. However the more utilized protocol for utilization of these implants requires a period of osseointegration of some months before the prosthetic restoration can be actually installed. Many times, to even of empirical way, for diminish this time of wait the original protocol is bad-tempered, diminishing the period of osseointegração. The objective of this work is going to present in a succinct way, the present stage of improvement the dental implants to optimize the trial of osseointegration, regarding the alterations of surface and of the form of these devices and to present the clinical results of 603 dual acid etched dental implants with healing chambers.

Influência do platform-switching no ambiente biomecânico de implantes em áreas estéticas – análise 3D em elementos finitos / Influence of platform-switching on the biomechanical environment of implant in esthetical zones – a 3D finite element analysis

O objetivo deste trabalho é avaliar a influencia do platform- switching nas deformações do osso peri-implantar e nas tensões do parafuso passante de implantes em áreas estéticas. Modelos em elementos finitos de um alvéolo de extração de um incisivo central superior, de um implante com 13 mm de comprimento por 4,5 de plataforma e de abutments com 4,5, 4,0 e 3,5 mm foram construídos. Os abutments de 4,0 e 3,5 mm acarretaram uma desadaptação horizontal de 0,5 e 1,0 mm (platform-switching), respectivamente. Um carregamento de 100 N foi aplicado sobre os abutments. Uma melhor distribuição de deformações no osso marginal peri-implantar são encontradas nos designes em platform-switching. Por outro lado, uma maior concentração de tensões no parafuso da prótese deve ser esperada para esta configuração.

The purpose of this study is to evaluate the influence of platform-switching configuration on the strain in periimplant bone and on the stress in the abutment screw. CT-based finite element models comprising an upper central incisor socket, a 13-mm implant with 4,5 mm of shoulder diameter and abutments of 4.5, 4.0 and 3.5 mm diameter were constructed. The abutments de 4.0 and 3.5 mm diameter represent the horizontal mismatch of 0.5 and 1.0 mm (platform-switching), respectively. 100 N magnitude load was applied over the abutments. A better strain distribution in periimplant marginal bone was encountered in platform- switching designs. On the other hand, a higher stress concentration could be found in the abutment screw.

Influência do desenho do implante na micromovimentação de implantes imediatos com carga imediata: análise multivariada em elementos finitos / Influence of implant design on the micromovement of immediately placed and loaded implants: a multivariate finite element analysis

O objetivo deste trabalho foi avaliar a influência do desenho do implante nas micromovimentações de implantes imediatos com carga imediata. Modelos em elementos finitos de um alvéolo de extração de um incisivo central superior e quatro desenhos de implantes de conexão interna, disponíveis comercialmente (SIN SW®, 3i Certain®, Nobel ReplaceTM e RN synOcta® ITI Standard), com diâmetros e comprimentos semelhantes foram construídos. Cargas de 50, 100 e 200 N foram aplicadas sobre os implantes. ANOVA com nível de 95% de significância foi utilizada para avaliar os dados da micromovimentação dos implantes. O design do implante influencia significativamente (31,21%) a micromovimentação de implantes imediatos com carga imediata. Não obstante, a intensidade da carga aplicada (68,80%) é o fator mais importante na estabilidade dos implantes neste protocolo.

The purpose of this paper was to evaluate the influence of different implant designs on the micromovements of immediately placed implants. CT-based finite element models comprising an upper central incisor socket and four commercially available internal connection implant designs (SIN SW®, 3i Certain®, Nobel ReplaceTM, and RN synOcta® ITI Standard) of comparable diameter and length were constructed. 50, 100 and 200N magnitude loads were applied over the implant. ANOVA at 95% level of significance was used to evaluate bone to implant relative displacement (micromovements). The implant design (68,80%) greatly influences the micromovement of immediately placed implants. However, the loading magnitude (68,80%) is the most important factor regarding the implant stability in this protocol.

Avaliação biomecânica de implantes imediatos com carga imediata: análise 3D em elementos finitos / Biomechanical evaluation of immediately placed implants: CT-based 3D finite element analysis

Objetivo: o objetivo do presente estudo foi analisar o ambiente biomecânico de implantes imediatos com carga imediata, comparando 3 diferentes magnitudes de carga. Material e Métodos: um modelo em elementos finitos de um incisivo central superior contendo um implante cônico de 13 mm de comprimento e 4,5 mm de plataforma, hexágono interno, foi construído. Elementos de contato friccional foram utilizados para simular as interfaces entre o osso, implante, abutment e parafuso do abutment. Foram aplicadas forças de 50, 100 e 200 N na extremidade superior do abutment. Os dados para a deformação equivalente no osso, as tensões equivalentes no parafuso, deslocamento relativo osso-implante e gap do abutment foram calculados. Resultados/Conclusão: a magnitude das cargas aplicadas sobre os implantes imediatos com carga imediata influenciam significativamente o ambiente biomecânico deste protocolo.

Objective: the purpose of the present study was to evaluate the biomechanical environment of immediately placed implants, by comparing three different loading magnitudes. Material and Methods: a CT-based finite element model of an upper central incisor extraction socket was constructed containing a conical internal hex 13-mm implant. Frictional contact elements were used in the bone, implant, abutment and abutment screw interfaces. Forces of 50, 100 and 200 N were applied on the superior central region of the abutment. Data for the peak equivalent strain in the bone, peak Von Mises stress in the abutment screw, bone-to-implant relative displacement and abutment gap were calculated. Results/Conclusion: the loading magnitudes applied over the implants are capable to greatly influence the biomechanical environment in immediately placed protocol.

Aplicabilidade do método de elementos finitos na implantodontia / Aplicability of finite elements method in implantology

A previsibilidade e o sucesso longitudinal do tratamento por implantes são altamente influenciados pelo ambiente biomecânico ao qual o implante é exposto. A concentração de tensão e deformação pode induzir reabsorção óssea e falhas como desaperto e fratura de parafusos. Neste sentido, o Método de Elementos Finitos tem sido utilizado como ferramenta para avaliação das tensões, deformações e deslocamentos gerados pelas cargas mastigatórias sobre os implantes osseointegráveis, com a finalidade de solucionar problemas estruturais complexos e prognosticar possíveis condições de falha. A expansão da utilização destes métodos é fundamentada em vantagens como custo relativamente baixo, versatilidade e a ausência de mutilações em animais ou humanos, além da confiabilidade comprovada pela larga utilização em diversas áreas do conhecimento. Este artigo tem por objetivo discutir a aplicabilidade do MEF na análise dos aspectos biomecânicos relacionados aos implantes dentais osseointegráveis. Este método foi detalhado didaticamente no que se refere á sua execução e à leitura dos resultados. Foram citados 44 estudos, selecionados no MedlineTM, tendo como critérios de inclusão a relevância do tema, a boa qualidade da metodologia e a importância do periódico onde estão publicados. As palavras-chave utilizadas foram: dental implants, immediate load, finite element, biomechanic e bone loss, em variadas combinações.

The previsibilty and the longitudinal sucess in the treatment with dental implants are highly influenced by the biomechanical conditions of the area where the implant will be installed. The load stress concentration and implant deformation, could facilitate the induction of perimplantar bone resorption as well as some failures and screw fracture. The finite elements method has been used as a tool for this kind of studies, to evaluate tensions, deformations and dislocations caused by masticatory forces on the osseointegrated implants. The finite elements method utilization has expanded in those research works considering its low cost, versatility and the absence of animals or patients, since it is mathematically done as a simulation in the computer. This method of study has acquired credibility in the literature and has been used in many different areas of acknowledgements. The purpose of finite elements method in the present research work is to discuss its applicability in relation to osseointegrated dental implants. It provides detailed results and its execution is not difficult. In the review of the literature 44 studies have been selected and presented considering the subject relevance, emphasizing the method quality and the important periodicals where the studies were published.

Estudo comparativo da topografia superficial de abutments de titânio de diferentes marcas comerciais / Comparative study of the superficial topography of abutments of titanium of differents commercials marks

Foram utilizados para o presente estudo sete intermediários de titânio para cada grupo de marca comercial, analisados pela técnica de interferometria a laser, a qual é executada através de um perfilômetro a laser, marca UBM, modelo MICROFOCUS EXPERT IV. As leituras realizadas foram subdivididas em áreas planas e inclinadas, de acordo com a anatomia do componente. Os dados obtidos foram processados pelo software DIGITAL SURF MOUNTAIS MAP UNIVERSAL® - Versão 3.1.9, o qual gerou imagens tridimensionais para uma aná-lise qualitativa da topografia superficial. Além disso, foram considerados pelo presente estudo o total de quatro parâmetros de rugosidade para a análise quantitativa. De acordo com os resultados, observouse que os intermediários de titânio analisados não demonstraram uniformidade nas suas características topográficas superficiais quando comparadas as áreas inclinadas e planas de um mesmo componente, independente da marca comercial. Além disso, nenhum dos grupos obteve médias de rugosidade média (Sa) iguais ou inferiores aquelas presentes na literatura científica.