Evaluation of Immediate Implants Augmented with Autogenous Bone/Melatonin Composite Graft in the Esthetic Zone: A Randomized Controlled Trial

Systemic Factors Affecting Prognosis of Dental Implants

Clinicians who place and restore implants are always concerned about the success and longevity of the same. There are several local and systemic factors that affect osseointegration and the health of the peri-implant tissues. In this study, we review the systemic factors that can affect implant survival, osseointegration, and long-term success. The study highlights the importance of delineating, and taking into consideration these systemic factors from the planning phase to the restorative phase of dental implants. A thorough medical history, including prescription and over-the-counter medications, is vital, as there may be numerous factors that could directly or indirectly influence the prognosis of dental implants.

Use of Local Melatonin with Xenogeneic Bone Graft to Treat Critical-Size Bone Defects in Rats with Osteoporosis: A Randomized Study

The aim of this study was to evaluate the effect of local administration of melatonin (MLT) on molecular biomarkers and calvaria bone critical defects in female rats with or without osteoporosis, associated or not with a xenogeneic biomaterial. Forty-eight female rats were randomly divided into two groups: (O) ovariectomized and (S) placebo groups. After 45 days of osteoporosis induction, two critical-size defects (5 mm diameter) were created on the calvaria. The groups were subdivided according to the following treatment: (C) Clot, MLT, MLT associated with Bio-Oss® (MLTBO), and Bio-Oss® (BO). After 45 days, the defect samples were collected and processed for microtomography, histomorphometry, and biomolecular analysis (Col-I, BMP-2, and OPN). All animals had one femur harvested to confirm the osteoporosis. Microtomography analysis demonstrated a bone mineral density reduction in the O group. Regarding bone healing, the S group presented greater filling of the defects than the O group; however, in the O group, the defects treated with MLT showed higher mineral filling than the other treatments. There was no difference between the treatments performed in the S group (p = 0.05). Otherwise, O-MLT had neoformed bone higher than in the other groups (p = 0.05). The groups that did not receive biomaterial demonstrated lower levels of Col-I secretion; S-MLT and S-MLTBO presented higher levels of OPN, while O-C presented statistically lower results (p < 0.05); O-BO showed greater BMP-2 secretion (p < 0.05). In the presence of ovariectomy-induced osteoporosis, MLT treatment increased the newly formed bone area, regulated the inflammatory response, and increased OPN expression.

Beneficial Effects of Melatonin on Periodontitis Management: Far More Than Oral Cavity

Periodontitis as a highly prevalent chronic infection/inflammatory disease can eventually lead to tooth loss and masticatory dysfunction. It also has a negative impact on general health and largely impairs quality of life. The tissue destruction during periodontitis is mainly caused by the excessive immune-inflammatory response; hence, how to modulate the host's reaction is of profound importance for effective periodontal treatment and tissue protection. Melatonin, as an endogenous hormone exhibiting multiple biological functions such as circadian rhythm regulation, antioxidant, and anti-inflammation, has been widely used in general healthcare. Notably, the past few years have witnessed increasing evidence for the application of melatonin as an adjunctive approach in the treatment of periodontitis and periodontitis-related systemic comorbidities. The detailed underlying mechanisms and more verification from clinical practice are still lacking, however, and further investigations are highly required. Importantly, it is essential to establish standard guidelines in the near future for the clinical administration of melatonin for periodontal health and general wellbeing.

Insights into the Role of Macrophage Polarization in the Pathogenesis of Osteoporosis

Millions of people worldwide suffer from osteoporosis, which causes bone fragility and increases the risk of fractures. Osteoporosis is closely related to the inhibition of osteogenesis and the enhancement of osteoclastogenesis. In addition, chronic inflammation and macrophage polarization may contribute to osteoporosis as well. Macrophages, crucial to inflammatory responses, display different phenotypes under the control of microenvironment. There are two major phenotypes, classically activated macrophages (M1) and alternatively activated macrophages (M2). Generally, M1 macrophages mainly lead to bone resorption, while M2 macrophages result in osteogenesis. M1/M2 ratio reflects the "fluid" state of macrophage polarization, and the imbalance of M1/M2 ratio may cause disease such as osteoporosis. Additionally, antioxidant drugs, such as melatonin, are applied to change the state of macrophage polarization and to treat osteoporosis. In this review, we introduce the mechanisms of macrophage polarization-mediated bone resorption and bone formation and the contribution to the clinical strategies of osteoporosis treatment.

Melatonin as an adjunctive treatment on dental procedures: A systematic review

The systematic review tried to answer the following question: Does the melatonin administered systemically or topically ameliorate patients involved with oral health conditions or dental procedures? The systematic review has been registered in the PROSPERO (2021CRD42021095959). Eligibility criteria included only randomized controlled clinical trials (RCTs) with at least 10 participants that compared patients that received melatonin as a treatment before and/or after their oral intervention topically or systemically, with control patients. A search was performed in PubMed/MEDLINE, Web of Science, Cochrane Library, and Academic Google databases for articles up to February 2021. The Cochrane risk-of-bias tool for randomized clinical trials was used and revealed that the studies included presented low risk of bias for the majority of criteria assessed. It was selected 25 articles, of which only six did not demonstrate positive effects and three presented null effects with the use of melatonin. Melatonin has improved the inflammatory response in periodontal disease, dental surgeries, and mucositis of head and neck oncologic irradiated patients. In addition, it showed anxiolytic potential in patients that were submitted to dental procedures. In conclusion, melatonin favored the treatment of oral changes when used topically and systemically.

Combination of bone substitutes and vectors in periodontology and implantology: A systematic review

The aim of the systematic review was to analyze the use of combination of bone substitutes and vectors in periodontology and implantology among animals models and humans. Electronic databases were searched, and additional hand search was performed. The research strategy was achieved according to the PRISMA guidelines. The including criteria were: combination of bone substitutes and vectors, in vivo studies, a precise number of specimens, histological and radiographic analysis, written in English. The risk of bias was evaluated for individual studies. Thirty-two articles were selected and investigated in this systematic review. The results do not show a superiority of the use of composite biomaterial in comparison with simple biomaterial but suggest the efficacity of their utilization as a carrier of bioactive agents. Future studies need to identify the suitable association of bone substitutes and vectors and explore interest in their use such as the support of growth factors.

Efficacy of different surgical techniques for peri-implant tissue preservation in immediate implant placement: a systematic review and meta-analysis

INTRODUCTION

Preserving peri-implant tissues after immediate implant placement (IIP), especially in aesthetic zones, is a topic of interest.

OBJECTIVES

This systematic review investigated the effects of currently available surgical procedures for preserving peri-implant tissue or ensuring dimensional stability following immediate implant placement.

MATERIALS AND METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement's guidelines were followed, and articles were sought on the PubMed and Cochrane databases with no date restrictions. Only randomised clinical trials that evaluated changes in soft and hard tissues around immediately placed implants were included. Statistical analyses were performed, and the studies´ quality was assessed using the Cochrane Collaboration tool. The agreement between reviewers was assessed based on Cohen's kappa statistics.

RESULTS

Of the 14 studies that met the inclusion criteria, 11 were analysed in the meta-analysis (kappa = 0.814; almost perfect agreement). The use of connective tissue grafts resulted in a significantly greater improvement of the facial gingival level (MD = -0.51; 95% CI: -0.76 to -0.31; p = < .001), and the placement of bone grafts significantly reduced the horizontal resorption of the buccal bone (MD = -0.59; 95% CI: -0.78 to -0.39; p < .001).

CONCLUSION

Connective tissue grafts and bone grafts positively influence tissue preservation around immediately placed implants. Neither the flapless technique nor palatal implant positioning resulted in significant improvements to any of the investigated parameters. Additional longitudinal studies are required.

CLINICAL RELEVANCE

This meta-analysis is useful for discerning the effects of soft tissue augmentation, bone grafting, the flapless technique, and palatal implant positioning on preserving peri-implant tissues after immediate implant placement.