Characterization and morphological methods for oral biofilm visualization: where are we nowadays?

The oral microbiome represents an essential component of the oral ecosystem whose symbiotic relationship contributes to health maintenance. The biofilm represents a state of living of microorganisms surrounding themselves with a complex and tridimensional organized polymeric support and defense matrix. The substrates where the oral biofilm adhere can suffer from damages due to the microbial community metabolisms. Therefore, microbial biofilm represents the main etiological factor of the two pathologies of dental interest with the highest incidence, such as carious pathology and periodontal pathology. The study, analysis, and understanding of the characteristics of the biofilm, starting from the macroscopic structure up to the microscopic architecture, appear essential. This review examined the morphological methods used through the years to identify species, adhesion mechanisms that contribute to biofilm formation and stability, and how the action of microbicidal molecules is effective against pathological biofilm. Microscopy is the primary technique for the morphological characterization of biofilm. Light microscopy, which includes the stereomicroscope and confocal laser microscopy (CLSM), allows the visualization of microbial communities in their natural state, providing valuable information on the spatial arrangement of different microorganisms within the biofilm and revealing microbial diversity in the biofilm matrix. The stereomicroscope provides a three-dimensional view of the sample, allowing detailed observation of the structure, thickness, morphology, and distribution of the various species in the biofilm while CLSM provides information on its three-dimensional architecture, microbial composition, and dynamic development. Electron microscopy, scanning (SEM) or transmission (TEM), allows the high-resolution investigation of the architecture of the biofilm, analyzing the bacterial population, the extracellular polymeric matrix (EPS), and the mechanisms of the physical and chemical forces that contribute to the adhesion of the biofilm to the substrates, on a nanometric scale. More advanced microscopic methodologies, such as scanning transmission electron microscopy (STEM), high-resolution transmission electron microscopy (HR-TEM), and correlative microscopy, have enabled the evaluation of antibacterial treatments, due to the potential to reveal the efficacy of different molecules in breaking down the biofilm. In conclusion, evidence based on scientific literature shows that established microscopic methods represent the most common tools used to characterize biofilm and its morphology in oral microbiology. Further protocols and studies on the application of advanced microscopic techniques are needed to obtain precise details on the microbiological and pathological aspects of oral biofilm.

The effects of surgical preparation techniques and implant macro-geometry on primary stability: An in vitro study

BACKGROUND: The attainment of a good primary stability is a necessary condition to ensure the success of osseointegration in implantology. In type IV cancellous bone, however, it is possible that a reduced primary stability can lead to an increased rate of failure. The aim of this study was therefore to determine, with the help of the resonance frequency (Osstell mentor), which technique of implant site preparation (piezo surgery, conventional, under-preparation, bone compaction, osteodistraction) and macro-geometry is able to improve implant stability in type IV cancellous bone. MATERIAL AND METHODS: 10 pig ribs were prepared with a surgical pre-drilled guide, calibrated for a correct implant positioning. On each rib, 5 implant sites (one for each technique) were prepared. Successively, 50 conical implants (Tekka Global D) were inserted and measured with the resonance frequency to evaluate the primary stability. Data collected were analyzed by analysis of variance (ANOVA) to test whether the Implant Stability Quotient (ISQ) values of the five techniques were significantly different. RESULTS: The results showed that no significant differences among the ISQ values of the five techniques used were found. Also, no significant differences in the macro-geometry of the two types of compared implants were observed. However, the macro-geometry of Tekka implants, characterized by a double condensing thread, seems to provide greater ISQ values than those of single thread implants when using the same technique. CONCLUSIONS: In light of these preliminary data, it is conceivable that in cases of reduced stability, such as those occurring with a type IV bone, all means ameliorating the primary stability and accelerating the osseointegration can be utilized

Use of 3D cartilage scaffolds for the stabilization of implants and bone regeneration with the fit-lock technique

Los procedimientos quirúrgicos para la aplicación de los implantes en los sectores latero superiores, están condicionadas por la neumatización del seno y la disponibilidad del huesoresidual. En estos casos el injerto de hueso autólogo permanece como lamejor opción, pero a causa de la morbilidad asociada al sitio donante y a las complicaciones post quirúrgicas, se pusieron a disposición diversas alternativas de sustitutos óseos, que implican sin embargo un aumento de los costos económicos y con limitadas propiedades osteoinductivas. Tales defectos pueden ser compensados con nuevas estrategias de regeneración biológica y mecánica de los tejidos a loscuales fue dirigida la ingeniería biológica y mecánica en los últimos años.Se presenta una nueva posibilidad terapéutica en la aplicación de los implantes en el maxilar superior con disponibilidad ósea inferior a los 4 mm, mediante la utilización de andamios 3D confeccionados en cartilago de cerdo libre de antígenos obtenido según la tecnica Fit-Lock. Se realizo un estudio longitudinal en 18 casos consecutivosevidenciando al cabo de un año de la carga implantológica, un éxito del 95,2 por ciento. Las ventajas en esta nueva técnica son: 1)La recuperación funcionaly anatómica del antro del maxilar 2).La aplicación inmediata de los implantes; 3)Reducción de los tiempos quirúrgicos; 4) Ausencia de morbilidad para el paciente; 5) Uso de anestesia local; 6)Uso de implantes con diámetros superiores a los 4 mm

Use of 3D cartilage scaffolds for the stabilization of implants and bone regeneration with the fit-lock technique. / Use of 3D cartilage scaffolds for the stabilization of implants and bone regeneration with the fit-lock technique.

The surgical procedures for implant applications on the lateral-upper areas depend on sinus pneumatization and availability of the residual bone. In these cases, autologous bone grafting remains the gold standard. Nevertheless, because of the morbidity associated to the donor site and the post-surgical complications, several alternative bone substitutes have been introduced, which, however, imply additional costs and show limited osteoinductive properties. Such limitations can be compensated with new regeneration strategies for biological and mechanical tissue restoration, a subject which has been addressed by tissue engineering in recent years. The authors present a new therapeutic option for implant application in the upper maxilla with bone availability less than 4 mm by using 3D scaffolds obtained from antigen-free porcine cartilage in the fit-lock technique. A longitudinal study on 18 consecutive cases was performed, with a 95.2

success rate one year after the implant. The advantages of this new technique are: 1) Functional and anatomical recovery of the maxillary antrum, 2) Immediate application of the implants; 3) Reduction of surgical times; 4) Absence of patient morbidity; 5) Local anesthesia; 6) Use of implants with a diameter > 4 mm.

Self-bone graft and simultaneous application of implants in the upper jawbone (fit lock technique)

La rehabilitación implanto soportada de los sectores posterosuperiores resulta, a veces, condicionada por la neumatizaciòndel seno maxilar, reduciendo la posibilidad de la aplicación delos implantes cuando la disponibilidad ósea es inferior a los 4 mm. (Condición Límite para la estabilidad primaria).El levantamiento del seno maxilar y la aplicación simultánea de los implantes es con seguridad la condición que mejorgarantiza el éxito, respecto a la sola aplicación del material de relleno. Muchas son las técnicas quirúrgicas desarrolladas en la utililizaciòn del hueso autòlogo (cresta iliaca, calota craneana, peroné) y la aplicación de los implantes. En este artículo se presenta una nueva técnica para reducir almínimo la invasividad de la toma del material óseo de injerto autólogo y la morbilidad del paciente. Se ha realizado un estudio longitudinal sobre 21 casos consecutivos, mostrando un éxito del 94,5 por ciento. Las ventajas de esta técnica son: 1) Recuperación funcional y anatómica del seno maxilar. 2) Aplicación inmediata de los implantes con un espesor residuo de hueso de piso de seno menor a los 4 mm. 3) Reducciónde los tiempos quirúrgicos. 4) Menor Morbilidad del paciente. 5) Anestesia loco regional.