Histochemical examination on the peri-implant bone with early occlusal loading after the immediate placement into extraction sockets

Abstract

Early and immediate loading of dental implants has become a routine procedure in dental practices throughout the world, but the histological feature of peri-implant bone has not been fully understood. Therefore, we aimed to elucidate the histological response of peri-implant bone bearing the early occlusal loading using rat models. Four-week-old male Wistar rats were subjected to extraction of their maxillary left first molars and had titanium implants inserted immediately into the post-extraction sockets. In experimental groups at 1 week after placement, implants were loaded for 1 or 2 weeks by adding adhesive resin on the top of the screws. In control groups, no adhesive resin was added to the implants. After 1 or 2 weeks with loading, rats were fixed with an aldehyde solution for histochemical assessment. Newly-formed bone adhered broadly to the implant surface in both the control and experimental groups. The experimental group loaded for 2 weeks showed thicker trabeculae between the implant threads compared to those in the control group. Osteopontin- and osteocalcin-positive cement lines, which are histological hallmarks of bone remodeling, were narrow and smooth in the experimental groups, while featuring a complex meshwork with thick scalloped lines in the control groups. The index of sclerostin-positive osteocytes located close to implants loaded for 2 weeks was significantly lower than in controls, suggesting that osteoblast activity was preserved. Summarizing, our experimental model suggested that early implant loading increases trabecular thickness in the peri-implant bone tissue in a process that involves the regulation of bone remodeling.

Cellular and Molecular Dynamics during Early Oral Osseointegration: A Comprehensive Characterization in the Lewis Rat

“…82−87 Further examination of either of these models will uncover a large variety in methodology. In extraction models, the placement of the implant is reported to be either immediately following tooth extraction [69][70][71]73,80 or up to 30 days after. 72,[74][75][76][77][78][79]81 Placement is also inconsistent, in bed of the first molar, 71,[73][74][75][76][77]79,81 anywhere between the first and second molar, 70 or the socket where the mesial root of the first molar is located before extraction.…”

“…In extraction models, the placement of the implant is reported to be either immediately following tooth extraction [69][70][71]73,80 or up to 30 days after. 72,[74][75][76][77][78][79]81 Placement is also inconsistent, in bed of the first molar, 71,[73][74][75][76][77]79,81 anywhere between the first and second molar, 70 or the socket where the mesial root of the first molar is located before extraction. 69,80 In nonextraction models, implantation into the maxillary diastema can occur anywhere anterior to the first molar and posterior of the incisor roots.…”

System for application of controlled forces on dental implants in rat maxillae: Influence of the number of load cycles on bone healing

“…There are only scattered reports on the osseointegration of implants in the oral cavity of rodents and these are, in general, under conditions of uncontrolled loading that essentially rely on placing the implant under the occlusion plane (Dunn et al, ; Ikeda et al, ; Lin et al, ; Mouraret et al, ). While this would shield from direct occlusal forces, it does not protect from tongue movements and food impact.…”

In focus in HCB

“…The four topmost downloaded papers are highly illustrative of this fact and include, "The peroxisome" by Islinger et al (2018), "The micromechanics of lung alveoli" by Knudsen and Ochs (2018), "Clathrin-independent endocytosis" by Sandvig et al (2018) and "Molecular imaging with nanoparticles" by Thurner and Debbage (2018). A Special Issue on "Hard Tissue Biology" edited by Amizuka and Kitazawa (2018) comprehensibly covered the molecular and cell biology of development, regeneration and metabolism of bone, cartilage and teeth (Goltzman 2018;Haraguchi et al 2018;Hasegawa 2018;Ikeda et al 2018;Komori 2018;Liu et al 2018;Nakatomi et al 2018;Nishimura et al 2018;Ono and Nakashima 2018) and their pathology (Kitazawa et al 2018a;Lui et al 2018;Nishimura et al 2018), aspects of tissue engineering (Hoshi et al 2018), and, last but not least, the application of advanced intravital multiphoton imaging (Mizuno et al 2018) and FIB-SEM (Hasegawa et al 2018). Further noticeable and highly read papers reported on various aspects of COPII-dependent ER export (McCaughey and Stephens 2018), the intermediate compartment (Saraste and Marie 2018), contact-mediated cell communication by cytonemes and tunneling nanotubes (Mattes and Scholpp 2018), the mammalian centrosome (Schatten and Sun 2018), nuclear actin (Bajusz et al 2018), the nucleolus (Schöfer and Weipoltshammer 2018;Stachecka et al 2018;Stępiński 2018), open questions of nuclear organization and genome architecture (Adriaens et al 2018), the epigenome (Kitazawa et al 2018b;Uličná et al 2018), human trophoblast invasion (Hiden et al 2018;…”