Pre-implantation mouse embryo movement under hormonally altered conditions

Precise regulation of embryo movement is crucial to successful implantation, but the role of ovarian hormones in this process is not understood. We ascertain the effects of altered hormonal environment on embryo movement using two delayed implantation models: Natural lactational Diapause (ND), a naturally occurring alternate model of pregnancy, and Artificially induced Diapause (AD), a laboratory version of ND. Our previous work suggests that embryos in a natural pregnancy (NP) first display unidirectional clustered embryo movement, followed by bidirectional scattering and spacing movement. In contrast, in the ND model, embryos are present as clusters near the oviductal-uterine junction for ~24-hours longer than NP, followed by locations consistent with a unidirectional scattering and spacing movement. Intriguingly, the AD model closely resembles embryo location in NP and not ND. Further, unlike the popular paradigm of reduced estrogen (E2) levels in diapause E2 levels are comparable across NP, ND, and AD, while progesterone (P4) levels are reduced in ND and highly increased in AD when compared to NP. Exogenous administration of E2 or P4 modifies the unidirectional clustered embryo movement, while E2 treatment causes a reduction in P4 and affects the bidirectional phase of embryo movement. Taken together, our data suggest embryo movement can be modulated by both P4 and E2. Understanding natural hormonal adaptation in diapause provides an opportunity to determine key players regulating embryo movement and implantation success. This knowledge can be leveraged to understand pregnancy survival and implantation success in hormonally altered conditions in the clinic.

Delayed implantation induced by letrozole in mice

Implantation timing is key for a successful pregnancy. Short delay in embryo implantation caused by targeted gene ablation produced a cascading problem in the later stages of the pregnancy. Although several delayed implantation models have been established in wild mice, almost none of them is suitable for investigating the delay on the late events of pregnancy. Here, we report a new delayed implantation model established by the intraperitoneally administration of letrozole at 5 mg/kg body weight on the day 3 of pregnancy. In these mice, initiation of implantation was induced at will by the injection of estradiol (E2). When the estradiol (3 ng) was injected on day 4 of pregnancy (i.e., without delay), the embryo implantation restarted, and the pregnancy continued normally. However, high dose of estrogen (25 ng) caused compromised implantation. We also found that only 67% of the female mice could be pregnant normally and finally gave birth when the injection of estradiol (3 ng) was on day 5 of pregnancy (i.e., one day delay). Most of the failed pregnancies had impaired decidualization, decreased plasma progesterone levels and compromised angiogenesis. Progesterone supplementation could rescue decidualization failure in the mice. Collectively, we established a new model of delayed implantation by letrozole, which can be easily used to study the effect and mechanisms of delay of embryo implantation on the progression of late pregnancy events.

CLINICAL STUDIES OF THE STABILITY AND PROCESS OF OSTEOINTEGRATION OF DENTAL IMPLANTS DURING IMMEDIATE AND DELAYED IMPLANTATION

Subject. Analysis of the literature confirms that there is a definite relationship between surface microstructure, implant geometry, thread design and primary stability, and osseointegration processes. To date, a sufficient number of works on direct and delayed implantation have accumulated. However, there is not enough convincing clinical data on the quantitative assessment of primary stability at different periods of the osseointegration process. Despite the existence of experimental and clinical observations, it seems impossible to make a definite judgment about the mechanism of such a relationship. This chapter presents clinical studies of the stability and osseointegration of dental implants when performing, according to the indications, in 414 patients of direct and delayed implantation using implant systems with different surface microstructures. Goal. Conduct clinical studies of quantitative indicators of stability and osseointegration of implants with different microstructure of the surface during direct and delayed implantation. Methodology. For the clinical study of primary stability and the process of osseointegration during direct and delayed implantation with immediate functional loading, implant systems with different surface microstructures were used: Alfa Bio, Mis, Astra-Tech, Dentium, Ostem, Antogher, and also Humana Dental with an innovative surface. Osseointegrated implants have been used to achieve a predictable treatment outcome in clinical cases with partial or complete adentia, as well as in the presence of single, included defects. Results. There were no significant differences in stability indicators at the time of implant placement in the alveolar bone, depending on the type of implant and the method of implantation. Conclusions. In the process of integration of the implant into the bone tissue at a later date, the indicators of stability and osseointegration improve. The relationship between the appearance of the implant surface, primary stability and the time of its adaptation was revealed.

Histological and X-ray structural analysis of the conditionof the bone tissue of the jaws with direct and delayed implantation using implants with different surface microstructures

This article presents the results of histological and X-ray studies of bone condition, stability, and degree of osteointegration of implants with different microstructure of the surface during immediate and delayed implantation in the animal experiment. The results of the study did not reveal significant differences in the process of osteointegration during direct and delayed implantation. Data from histological and X-ray studies of direct implantation in fresh extraction holes are comparable to those obtained during delayed implantation and are not inferior to the traditional two-stage protocol. At the same time, a certain correlation between the type of surface of the implant and the time of its adaptation in different periods of the experiment was revealed. When using an implant with an innovative surface, HSTTM. The process of osteointegration is mor clear, and the bone wall of the hole is more compacted, which indicates an accelerated and successful process of osteointegration. Key words: X-ray diffraction, frequency resonance and histological analysis, fibrous capsule, collagen fibers, trabeculae, bone tissue, periotestometry osseointegration, stability.

The effect of microstructure of the surface, the design and dimension of dental implants on their stability and the process of osteointegration during immediate and delayed implantation. PartII

This article presents the results of a clinical study of the stability and process of osteointegration implants of 11 known implant dental systems. The effect of the microstructure of 3 types of implant surface (HSTTM, SLA and RBM) and their design features (shape, size, type of carving) on the indicators of their stability and osteointegration process during immediate and delayed implantation with immediate functional load is shown and analyzed. The stability of the implants and the dynamics of the quality of osteointegration were determined by the devices «Osstell Mentor» and «Periotest» in the process of treatment, starting from the moment of implant installation in different eras (2 weeks, 1 month, 2 months and 3 months). 414 patients between the ages of 20 and 70 were monitored. Of these, there are 249 and 165 male women. The average age of the operated patients was: for men – 54 years for women – 49 years. All patients were divided into two groups of the first – 109 patients who after extraction were directly implanted into the hole of the remote tooth with the subsequent immediate load, the second group – 305 patients who were delayed implantation with immediate load. A total of 1,302 implants were installed. The study revealed a link between the type of surface of the implant, primary stability and the time of its osteointegration during certain periods of clinical observation. The results of the study demonstrated the important role of combining microstructure of the surface, design and dimension features, the type of insertion of implants on their primary stability and the process of osteointegration in the conduct of both immediate and delayed implantation. Key words: frequency resonance analysis, damping, stability, osteointegration, fixation, implants, periotestometry, immediate implantation.

The effect of microstructure of the surface, the design and dimension of dental implants on their stability and the process of osteointegration during immediate and delayed implantation

This article presents the results of a clinical study of the stability and process of osteointegration implants of 11 known implant dental systems. The effect of the microstructure of 3 types of implant surface (HSTTM, SLA and RBM) and their design features (shape, size, type of carving) on the indicators of their stability and osteointegration process during immediate and delayed implantation with immediate functional load is shown and analyzed. The stability of the implants and the dynamics of the quality of osteointegration were determined by the devices «Osstell Mentor» and «Periotest» in the process of treatment, starting from the moment of implant installation in different eras (2 weeks, 1 month, 2 months and 3 months). 414 patients between the ages of 20 and 70 were monitored. Of these, there are 249 and 165 male women. The average age of the operated patients was: for men – 54 years for women – 49 years. All patients were divided into two groups of the first – 109 patients who after extraction were directly implanted into the hole of the remote tooth with the subsequent immediate load, the second group – 305 patients who were delayed implantation with immediate load. A total of 1,302 implants were installed. The study revealed a link between the type of surface of the implant, primary stability and the time of its osteointegration during certain periods of clinical observation. The results of the study demonstrated the important role of combining microstructure of the surface, design and dimension features, the type of insertion of implants on their primary stability and the process of osteointegration in the conduct of both immediate and delayed implantation. Key words: frequency resonance analysis, damping, stability, osteointegration, fixation, implants, periotestometry, immediate implantation.

Accuracy of Full-Guided and Half-Guided Surgical Templates in Anterior Immediate and Delayed Implantation: A Retrospective Study

Computer-aided implantology has developed rapidly in recent years, this study aimed to compare the accuracy of guided-surgery between anterior immediate and delayed implantation, and simultaneously assess the effect of full-guided and half-guided templates on accuracy values. Seventy-six implants were inserted in 63 patients using full-guided or half-guided template in the anterior zone. Postoperative cone beam computed tomography (CBCT) was matched with preoperative planning to evaluate the deviation between actual and planned implants. No statistical difference was found in any deviation between immediate and delayed implantation (p > 0.05). In anterior immediate implantation, the global coronal, apical, depth and angular deviations of full-guided templates were all significantly lower than those of half-guided templates (0.66 ± 0.26 vs. 1.10 ± 0.76 mm, 0.96 ± 0.41 vs. 1.43 ± 0.70 mm, 0.46 ± 0.24 mm vs. 0.93 ± 0.79 mm and 1.69° ± 0.94° vs. 2.57° ± 1.57°). While in delayed implantation, full-guided templates only perform better with statistical significance on global apical and depth deviation (1.01 ± 0.42 vs. 1.51 ± 0.55 mm and 0.32 ± 0.26 vs. 0.71 ± 0.47 mm). After excluding the influence of depth deviation, the coronal and apical deviations between the two systems in immediate implantation and the apical deviations in delayed implantation had no statistical difference. Within the limit of this study, the results suggested the accuracy of guided-surgeries for anterior immediate and delayed implantations was comparable, and full-guided template was more accurate for immediate and delayed implantation.