Tesis Doctoral
Colocación inmediata de implantes con diferentes diseños: un estudio histológico, immunohistoquímico, molecular, de rayos x de alta resolución en animal
Autor/es | Giammarinaro, Enrica |
Director | Marconcini, Simone
Velasco-Ortega, Eugenio |
Departamento | Universidad de Sevilla. Departamento de Estomatología |
Fecha de publicación | 2024-03-18 |
Fecha de depósito | 2024-05-28 |
Resumen | Introduction. The long term success of dental implants depends on many
factors, am ong those: the accurate diagnosis and treatment planning with
regards to the patient’s local and systemic risk factors, ideal implant
position, ... Introduction. The long term success of dental implants depends on many factors, am ong those: the accurate diagnosis and treatment planning with regards to the patient’s local and systemic risk factors, ideal implant position, implant type, implant abutment connection type, prosthetic rehabilitation, and professional and domestic hygiene maintenance. The stability of peri implant tissues can be influenced by various etiological factors such as factors related to the patient ( systemic diseases, smoking , periodontal background, oral hygiene, parafunctional habits), with implant surgery (bone volume and quality, presence of keratinized gingiva, surgical technique as submerged or non submerged technique), with the characteristics of the implant (type of surface, macrodesign, type of connection) and with the prosthetic design (retention, type of abutme nts, prosthetic structure) The integrity of both the epithelial lining and the supracrestal connective tissue is required to maintain implant health for a long time. Recently, few authors have contributed to the redefinition of peri impl ant mucosa, providing the term imp lant supracrestal complex . The ISC includes the peri implant tissue the sulcus, the junctional epithelium, the connective tissue and the implant abutment prosthesis (IAP) complex. Thus, it is unreasonable to speak of supracrestal tissues without mentioning the type and location of the implant/abutment interface. Abutment structure and design has been suggested to have a relevant role in the formation of the peri implant soft tissues, their aesthetics and their long term stability. Over the past years, many different abutment shapes have been proposed in the literature, from scalloped and platform switched designs to concave abutments; these latter abutments present an inward narrowed profile that produces a macroscopic groove. The aim of this thesis is the comparison of t wo implants with identical bodies but different healing abutment geometries at the configuration of peri implant soft tissues. Material and methods. Two swine (sus scrofa), aged on average three years old, were acclimated for a three-week period prior to the initiation of the study. The two animals were identified using an ear tag. An antibiotic- free diet, softened by soaking in water, was provided. the Test one presented a 2 mm concave area above the implant platform, chosen according to the positive results reported in a histological animal study and a clinical study with a similar concave profile, whereas the Control abutment had a parallel walled healing screw. Animals had implants placed in the left or right mandibular alveolar ridges. Implants were either placed in the physiological mature bone present between the lower canine and first premolar or at the mandibular premolar region, within tooth extraction sites. All implants received a healing abutment at the time of placement. Implants were allowed three weeks of healing. Block sections were retrieved using an oscillating autopsy saw to keep the soft tissue intact. Samples of peri-implant soft tissues for histological analysis were fixed by immersion in 10% buffered formalin, dehydrated in increasing series of alcoholic rinses, and finally embedded in glycolmethacrylate resin. For EM qualitative and quantitative analysis small samples were taken from a ring of tissue dissected all around the area of the abutment. The ultrastructural analysis of collagen from peri- implant soft tissues was mostly performed in images showing the cross-sectional appearance of the collagen fibers, taken from longitudinal sections of the tissues. Results. After 12 weeks, proper histologic healing was observed around both CTRL and TEST implants. The radiographic exams also revealed a good osseointegration of all implants. Histological results showed the presence of peri-implant soft tissues in close connection with both Test and Control abutments. However, although this is only a qualitative finding, the soft tissue appears more adherent to the concave abutment than the straight one. Specifically, comparing the different appearance of collagen distribution and organization allowed us to divide samples into two groups: Control specimens, in which an extensive aggregation of thick collagen bundles was rare or absent, and Test samples containing a high-density large aggregation of tightly packed and sorted collagen fiber bundles. Conclusions. The present study on the peri-implant connective tissue structure evaluated by histological and TEM analysis showed that the concave transmucosal design could favor the deposition and growth of the connective tissue. This concavity generated a significant amount of connective tissue in the early healing phase, increased the thickness of this circular peri-implant network, and promoted the convergence of collagen fibers toward the abutment collar with the formation of a wide circular collagen structure over the implant platform. |
Cita | Giammarinaro, E. (2024). Colocación inmediata de implantes con diferentes diseños: un estudio histológico, immunohistoquímico, molecular, de rayos x de alta resolución en animal. (Tesis Doctoral Inédita). Universidad de Sevilla, Sevilla. |
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