Is micronucleus assay a useful marker in gingiva, tongue, and palate for evaluating cytogenetic damage induced by chemical, physical, and biological agents in vivo? A systematic review with meta-analysis.

The present systematic review (SR) aims to evaluate manuscripts in order to help further elucidate the following question: is the micronucleus assay (MA) also a useful marker in gingiva, tongue, and palate for evaluating cytogenetic damage in vivo? A search was performed through the electronic databases PubMed/Medline, Scopus, and Web of Science, all studies published up to December 2023. The comparisons were defined as standardized mean difference (SMD), and 95% confidence intervals (CIs) were established. Full manuscripts from 34 studies were carefully selected and reviewed in this setting. Our results demonstrate that the MA may be a useful biomarker of gingival tissue damage in vivo, and this tissue could be a useful alternative to the buccal mucosa. The meta-analysis analyzing the different sites regardless of the deleterious factor studied, the buccal mucosa (SMD = 0.69, 95% CI, - 0.49 to 1.88, p = 0.25) and gingiva (SMD = 0.31, 95% CI, - 0.11 to 0.72, p = 0.15), showed similar results and different outcome for the tongue (SMD = 1.19, 95% CI, 0.47 to 1.91, p = 0.001). In summary, our conclusion suggests that the MA can be a useful marker for detecting DNA damage in gingiva in vivo and that this tissue could be effective site for smearing.

Fish collagen for skin wound healing: a systematic review in experimental animal studies.

Collagen extracted from fishes has been appearing as an alternative for commercial porcine and bovine collagen and it has been considered interesting especially for membrane manufacturing in tissue engineering. Despite the positive in vitro effects of fish collagen membranes, there is still no understanding of all the benefits that this natural biomaterial plays in the wound healing process, due to the lack of compilation of the results obtained in animal studies. In this sense, the purpose of this study was to perform a systematic review of the literature to examine the effects of fish collagen membranes for skin wound healing in experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "fish," collagen," "skin," and "in vivo". A total of 10 articles were retrieved from the databases PubMed and Scopus. After the elegibility analyses, this review covers the different origins of fish collagen reported in the different papers from the beginning of 2015 through the middle of 2021. The results were based mainly on histological analysis and macroscopic evaluation, and fish skin collagen was responsible for improving the wound healing rate and the process of reepithelization and collagen deposition. In conclusion, fish skin collagen has shown positive results in in vivo studies and may be a potential biomaterial in tissue engineering.

Assessment of genotoxicity of glass ionomer cements: a systematic review.

To evaluate, through a systematic review, the assessment of genotoxicity of glass ionomer cements in vitro and in vivo. A systematic review was performed with the problem, intervention, control, and outcomes (PICOS) strategy, aiming to answer the following question: "Can glass ionomer cements induce genetic damage in vitro and in vivo?" A systematic search was performed in the following electronic databases: PubMed (including MedLine), Web of Science, and Scopus. The quality of included studies was assessed using the Effective Public Health Practice Project (EPHPP). After the authors performed the review of all articles, a total of 13 manuscripts met all the inclusion criteria in the systematic review. Following the parameters of the EPHPP, eight articles were classified as strong or moderate quality. The other ones (five studies) were weak. Taken together our results demonstrated that, six studies reported genotoxicity of the modified glass ionomer cements tested and two studies concluded that the effect of genotoxicity was time dependent.

In vitro and in vivo biological performance of hydroxyapatite from fish waste.

The aim of this study was to evaluate biocompatibility of hydroxyapatite (HAP) from fish waste using in vitro and in vivo assays. Fish samples (whitemouth croaker - Micropogonias furnieri) from the biowaste was used as HAP source. Pre-osteoblastic MC3T3-E1 cells were used in vitro study. In addition, bone defects were artificially created in rat calvaria and filled with HAP in vivo. The results demonstrated that HAP reduced cytotoxicity in pre-osteoblast cells after 3 and 6 days following HAP exposure. DNA concentration was lower in the HAP group after 6 days. Quantitative RT-PCR did not show any significant differences (p > 0.05) between groups. In vivo study revealed that bone defects filled with HAP pointed out moderate chronic inflammatory cells with slight proliferation of blood vessels after 7 and 15 days. Chronic inflammatory infiltrate was absent after 30 days of HAP exposure. There was also a decrease in the amount of biomaterial, being followed by newly formed bone tissue. All experimental groups also demonstrated strong RUNX-2 immoexpression in the granulation tissue as well as in cells in close contact with biomaterial. The number of osteoblasts inside the defect area was lower in the HAP group when compared to control group after 7 days post-implantation. Similarly, the osteoblast surface as well as the percentage of bone surface was higher in control group when compared with HAP group after 7 days post-implantation. Taken together, HAP from fish waste is a promising possibility that should be explored more carefully by tissue-engineering or biotechnology.

Bioglass/PLGA associated to photobiomodulation: effects on the healing process in an experimental model of calvarial bone defect.

Bioactive glasses (BG) are known for their ability to bond to bone tissue. However, in critical situations, even the osteogenic properties of BG may be not enough to induce bone consolidation. Thus, the enrichment of BG with polymers such as Poly (D, L-lactic-co-glycolic) acid (PLGA) and associated to photobiomodulation (PBM) may be a promising strategy to promote bone tissue healing. The aim of the present study was to investigate the in vivo performance of PLGA supplemented BG, associated to PBM therapy, using an experimental model of cranial bone defect in rats. Rats were distributed in 4 different groups (Bioglass, Bioglass/PBM, Bioglas/PLGA and BG/PLGA/PBM). After the surgical procedure to induce cranial bone defects, the pre-set samples were implanted and PBM treatment (low-level laser therapy) started (808 nm, 100 mW, 30 J/cm2). After 2 and 6 weeks, animals were euthanized, and the samples were retrieved for the histopathological, histomorphometric, picrosirius red staining and immunohistochemistry analysis. At 2 weeks post-surgery, it was observed granulation tissue and areas of newly formed bone in all experimental groups. At 6 weeks post-surgery, BG/PLGA (with or without PBM) more mature tissue around the biomaterial particles. Furthermore, there was a higher deposition of collagen for BG/PLGA in comparison with BG/PLGA/PBM, at second time-point. Histomorphometric analysis demonstrated higher values of BM.V/TV for BG compared to BG/PLGA (2 weeks post-surgery) and N.Ob/T.Ar for BG/PLGA compared to BG and BG/PBM (6 weeks post-surgery). This current study concluded that the use of BG/PLGA composites, associated or not to PBM, is a promising strategy for bone tissue engineering.

Bioactive glass-ceramic bone repair associated or not with autogenous bone: a study of organic bone matrix organization in a rabbit critical-sized calvarial model.

OBJECTIVE: The aim of the study was to analyze bone matrix (BMX) organization after bone grafting and repair using a new bioactive glass-ceramic (Biosilicate®) associated or not with particulate autogenous bone graft. MATERIAL AND METHODS: Thirty rabbits underwent surgical bilateral parietal defects and divided into groups according to the materials used: (C) control-blood clot, (BG) particulate autogenous bone, (BS) bioactive glass-ceramic, and BG + BS. After 7, 14, and 30 days post-surgery, a fragment of each specimen was fixed in - 80 °C liquid nitrogen for zymographic evaluation, while the remaining was fixed in 10% formalin for histological birefringence analysis. RESULTS: The results of this study demonstrated that matrix organization in experimental groups was significantly improved compared to C considering collagenous organization. Zymographic analysis revealed pro-MMP-2, pro-MMP-9, and active (a)-MMP-2 in all groups, showing gradual decrease of total gelatinolytic activity during the periods. At day 7, BG presented more prominent gelatinolytic activity for pro-MMP-2 and 9 and a-MMP-2, when compared to the other groups. In addition, at day 7, a 53% activation ratio (active form/[active form + latent form]) was evident in C group, 33% in BS group, and 31% in BG group. CONCLUSION: In general, BS allowed the production of a BMX similar to BG, with organized collagen deposition and MMP-2 and MMP-9 disponibility, permitting satisfactory bone remodeling at the late period. CLINICAL RELEVANCE: The evaluation of new bone substitute, with favorable biological properties, opens the possibility for its use as a viable and efficient alternative to autologous bone graft.

Experimental maxillary sinus augmentation using a highly bioactive glass ceramic.

Physicochemical characteristics of a biomaterial directly influence its biological behavior and fate. However, anatomical and physiological particularities of the recipient site also seem to contribute with this process. The present study aimed to evaluate bone healing of maxillary sinus augmentation using a novel bioactive glass ceramic in comparison with a bovine hydroxyapatite. Bilateral sinus augmentation was performed in adult male rabbits, divided into 4 groups according to the biomaterial used: BO-particulate bovine HA Bio-Oss(®) (BO), BO+G-particulate bovine HA + particulate autogenous bone graft (G), BS-particulate glass ceramic (180-212 µm) Biosilicate(®) (BS), and BS+G-particulate glass ceramic + G. After 45 and 90 days, animals were euthanized and the specimens prepared to be analyzed under light and polarized microscopy, immunohistochemistry, scanning electron microscopy (SEM), and micro-computed tomography (µCT). Results revealed different degradation pattern between both biomaterials, despite the association with bone graft. BS caused a more intense chronic inflammation with foreign body reaction, which led to a difficulty in bone formation. Besides this evidence, SEM and µCT confirmed direct contact between newly formed bone and biomaterial, along with osteopontin and osteocalcin immunolabeling. Bone matrix mineralization was late in BS group but became similar to BO at day 90. These results clearly indicate that further studies about Biosilicate(®) are necessary to identify the factors that resulted in an unfavorable healing response when used in maxillary sinus augmentation.

The use of micronucleus assay in exfoliated oral cells in patients undergoing fixed orthodontic therapy: a systematic review with meta-analysis.

The aim of this systematic review was to evaluate published papers regarding the micronucleus assay in oral mucosal cells of patients undergoing orthodontic therapy (OT). A search of the scientific literature was made in the PubMed, Scopus, and Web of Science databases for all data published until November, 2021 using the combination of the following keywords: "fixed orthodontic therapy," "genetic damage", "DNA damage," "genotoxicity", "mutagenicity", "buccal cells", "oral mucosa cells," and "micronucleus assay". The systematic review was designed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Nine studies were retrieved. Some authors demonstrated that OT induces cytogenetic damage in oral mucosal cells. Out of the nine studies included, two were classified as strong, five as moderate, and two as weak, according to the quality assessment components of the Effective Public Health Practice Project (EPHPP). Meta-analysis data revealed no relationship between mutagenicity in oral cells and OT in different months of treatment. At one month, the SMD = 0.65 and p = 0.08; after three months of OT, the SMD = 1.21 and p = 0.07; and after six months of OT, the SMD = 0.56 and p = 0.11. In the analyzed months of OT, I2 values were >75%, indicating high heterogeneity. In summary, this review was not able to demonstrate that OT induces genetic damage in oral cells. The study is important for the protection of patients undergoing fixed OT, given that mutagenesis participates in the multi-step process of carcinogenesis.

The role of fluoride on the process of titanium corrosion in oral cavity.

Titanium is known to possess excellent biocompatibility as a result of corrosion resistance, lack of allergenicity when compared with many other metals. Fluoride is well known as a specific and effective caries prophylactic agent and its systemic application has been recommended widely over recent decades. Nevertheless, high fluoride concentrations impair the corrosion resistance of titanium. The purpose of this article is to summarize the current data regarding the influence of fluoride on titanium corrosion process in the last 5 years. These data demonstrate noxious effects induced by high fluoride concentration as well as low pH in the oral cavity. Therefore, such conditions should be considered when prophylactic actions are administrated in patients containing titanium implants or other dental devices.

A novel bioactive vitroceramic presents similar biological responses as autogenous bone grafts.

Bioactive glasses represent an interesting class of bone substitute's biomaterials. The present study investigated the repair of bone defects filled with a novel bioactive vitroceramic (Biosilicate(®)), alone or in association with particulate autogenous bone grafts in calvaria defects of rabbits. After 7, 14, and 30 days the specimens were retrieved for histological, histomorphometric and immunohistochemistry analysis. Satisfactory bone formation was observed in all groups, and direct bone-biomaterial surface was noted. Histomorphometric assessment did not show statistically significant differences in bone formation among the groups and periods, except for BG group at day 14. Immunoexpression of Runx-2 was similar among the groups containing the graft and the biomaterial, being more intense than in control group. Similar result was observed for VEGF expression, especially in the last experimental period. These results revealed that Biosilicate(®) presented a favorable behavior, comparable to autogenous bone graft.

Cytotoxicity, Inflammatory Activity, and Angiogenesis Are Induced by Different Silicone Implants.

BACKGROUND/AIM: The aim of this study was to investigate cytotoxicity, inflammatory response, and angiogenesis induced by silicone gel breast implants with different textured surfaces in vitro and in vivo. MATERIALS AND METHODS: In the in vitro study, murine fibroblast cells (L929) were cultured for 1, 3, and 5 days with silicone membranes of three different textures: nanotextured, microtextured, and silicone foam. In the in vivo study, a total of 30 male rats (Rattus, norvegicus, albinos, Wistar) were distributed into three groups (10 animals per group), with 2 implants in each rat: nanotextured silicone gel breast implants group, microtextured silicone gel breast implants group, and silicone gel breast foam implants group. RESULTS: The Alamar Blue assay detected higher viability of cells cultured in the presence of nanotextured silicone surface for 1 and 3 days. The MTT assay showed higher cytotoxicity of silicone foam after 1 and 3 days of exposure. Nanotextured silicone breast implants induced a more prolonged inflammatory response, denoting a delay in the healing process and subsequent organization of the fibrous capsule as depicted by the collagen fiber types found. VEGF expression did not differ between experimental groups. CONCLUSION: Gel foam breast implants are more biocompatible when compared to micro- or nano-textured silicone breast implants.

Bone substitutes and photobiomodulation in bone regeneration: A systematic review in animal experimental studies.

In general, bone fractures are able of healing by itself. However, in critical situations such as large bone defects, poor blood supply or even infections, the biological capacity of repair can be impaired, resulting in a delay of the consolidation process or even in non-union fractures. Thus, technologies able of improving the process of bone regeneration are of high demand. In this context, ceramic biomaterials-based bone substitutes and photobiomodulation (PBM) have been emerging as promising alternatives. Thus, the present study performed a systematic review targeting to analyze studies in the literature which investigated the effects of the association of ceramic based bone substitutes and PBM in the process of bone healing using animal models of bone defects. The search was conducted from March and April of 2019 in PubMed, Web of Science and Scopus databases. After the eligibility analyses, 16 studies were included in this review. The results showed that the most common material used was hydroxyapatite (HA) followed by Biosilicate associated with infrared PBM. Furthermore, 75% of the studies demonstrated positive effects to stimulate bone regeneration from association of ceramic biomaterials and PBM. All studies used low-level laser therapy (LLLT) device and the most studies used LLLT infrared. The evidence synthesis was moderate for all experimental studies for the variable histological analysis demonstrating the efficacy of techniques on the process of bone repair stimulation. In conclusion, this review demonstrates that the association of ceramic biomaterials and PBM presented positive effects for bone repair in experimental models of bone defects.

Collagen from Marine Sources and Skin Wound Healing in Animal Experimental Studies: a Systematic Review.

Collagen (Col) from marine organisms has been emerging as an important alternative for commercial Col and it has been considered highly attractive by the industry. Despite the positive effects of Col from marine origin, there is still limited understanding of the effects of this natural biomaterial in the process of wound healing in animal studies. In this context, the purpose of this study was to perform a systematic review of the literature to examine the effects of Col from different marine species in the process of skin tissue healing using experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "marine collagen," "spongin," "spongin," "skin," and "wound." A total of 42 articles were retrieved from the databases PubMed and Scopus. After the eligibility analyses, this review covers the different marine sources of Col reported in 10 different papers from the beginning of 2011 through the middle of 2019. The results were based mainly on histological analysis and it demonstrated that Col-based treatment resulted in a higher deposition of granulation tissue, stimulation of re-epitalization and neoangiogenesis and increased amount of Col of the wound, culminating in a more mature morphological aspect. In conclusion, this review demonstrates that marine Col from different species presented positive effects on the process of wound skin healing in experimental models used, demonstrating the huge potential of this biomaterial for tissue engineering proposals.

Low level laser therapy does not modulate the outcomes of a highly bioactive glass-ceramic (Biosilicate) on bone consolidation in rats.

The main purpose of the present work was to evaluate if low level laser therapy (LLLT) can improve the effects of novel fully-crystallized glass-ceramic (Biosilicate) on bone consolidation in tibial defects of rats. Forty male Wistar rats with tibial bone defects were used. Animals were divided into four groups: group bone defect control (CG); group bone defect filled with Biosilicate (BG); group bone defect filled with Biosilicate, irradiated with LLLT, at 60 J cm(-2) (BG 60) and group bone defect filled with Biosilicate, irradiated with LLLT, at 120 J cm(-2) (BG 120). A low-energy GaAlAs 830 nm, CW, 0.6 mm beam diameter, 100 W cm(-2), 60 and 120 J cm(-2) was used in this study. Laser irradiation was initiated immediately after the surgery procedure and it was performed every 48 h for 14 days. Fourteen days post-surgery, the three-point bending test revealed that the structural stiffness of the groups CG and BG was higher than the values of the groups BG60 and BG120. Morphometric analysis revealed no differences between the control group and the Biosilcate group. Interestingly, the groups treated with Biosilicate and laser (BG 60 and BG120) showed statistically significant lower values of newly formed bone in the area of the defect when compared to negative control (CG) and bone defect group filled with Biosilicate (CB). Our findings suggest that although Biosilicate exerts some osteogenic activity during bone repair, laser therapy is not able to modulate this process.

Marine spongin incorporation into Biosilicate® for tissue engineering applications: An in vivo study.

Biomaterials and bone grafts, with the ability of stimulating tissue growth and bone consolidation, have been emerging as very promising strategies to treat bone fractures. Despite its well-known positive effects of biosilicate (BS) on osteogenesis, its use as bone grafts in critical situations such as bone defects of high dimensions or in non-consolidated fractures may not be sufficient to stimulate tissue repair. Consequently, several approaches have been explored to improve the bioactivity of BS. A promising strategy to reach this aim is the inclusion of an organic part, such as collagen, in order to mimic bone structure. Thus, the present study investigated the biological effects of marine spongin (SPG)-enriched BS composites on the process of healing, using a critical experimental model of cranial bone defect in rats. Histopathological and immunohistochemistry analyzes were performed after two and six weeks of implantation to investigate the effects of the material on bone repair (supplemental material-graphical abstract). Histological analysis demonstrated that for both BS and BS/SPG, similar findings were observed, with signs of material degradation, the presence of granulation tissue along the defect area and newly formed bone into the area of the defect. Additionally, histomorphometry showed that the control group presented higher values for Ob.S/BS (%) and for N.Ob/T.Ar (mm2) (six weeks post-surgery) compared to BS/SPG and higher values of N.Ob/T.Ar (mm2) compared to BS (two weeks post-surgery). Moreover, BS showed higher values for OV/TV (%) compared to BS/SPG (six weeks post-surgery). Also, VEGF immunohistochemistry was increased for BS (two weeks post-surgery) and for BS/SPG (six weeks) compared to CG. TGFb immunostaining was higher for BS compared to CG. The results of this study demonstrated that the BS and BS/SPG scaffolds were biocompatible and able to support bone formation in a critical bone defect in rats. Moreover, an increased VEGF immunostaining was observed in BS/SPG.

Evaluation of the In Vivo Biological Effects of Marine Collagen and Hydroxyapatite Composite in a Tibial Bone Defect Model in Rats.

One of the most promising strategies to improve the biological performance of bone grafts is the combination of different biomaterials. In this context, the aim of this study was to evaluate the effects of the incorporation of marine spongin (SPG) into Hydroxyapatite (HA) for bone tissue engineering proposals. The hypothesis of the current study is that SPG into HA would improve the biocompatibility of material and would have a positive stimulus into bone formation. Thus, HA and HA/SPG materials were produced and scanning electron microscopy (SEM) analysis was performed to characterize the samples. Also, in order to evaluate the in vivo tissue response, samples were implanted into a tibial bone defect in rats. Histopathological, immunohistochemistry, and biomechanical analyses were performed after 2 and 6 weeks of implantation to investigate the effects of the material on bone repair. The histological analysis demonstrated that composite presented an accelerated material degradation and enhanced newly bone formation. Additionally, histomorphometry analysis showed higher values of %BV/TV and N.Ob/T.Ar for HA/SPG. Runx-2 immunolabeling was higher for the composite group and no difference was found for VEGF. Moreover, the biomechanical analysis demonstrated similar values for all groups. These results indicated the potential of SPG to be used as an additive to HA to improve the biological performance for bone regeneration applications. However, further long-term studies should be carried out to provide additional information regarding the material degradation and bone regeneration.

Distinct healing pattern of maxillary sinus augmentation using the vitroceramic Biosilicate®: Study in rabbits.

OBJECTIVES: To follow healing process of augmented maxillary sinus in rabbits analyzing the histological pattern of bone tissue formation, along with the osteogenic activity and vascularization using a bioactive vitroceramic in comparison to deproteinized bovine bone associated or not with autogenous bone graft. DESIGN: Forty five male adult New Zealand rabbits, 5 months of age, mean weight of 4 Kg, underwent bilateral sinus augmentation surgeries to be divided in five groups: G - (Control) particulate autogenous bone graft (AG), BO - deproteinized bovine bone, BO+G - deproteinized bovine bone + AG, BSi -vitroceramic, and BSi + G - vitroceramic +AG. After 15, 45 and 90 days, all animals were euthanized for specimen's removal to be analyzed under light microscopy, histomorphometry, and immunohistochemistry for Runx2 and VEGF labeling. RESULTS: G, BO and BO+G groups healed uneventfully, allowing the formation of mature remodeling bone at day 90, regarding the association of AG with the biomaterial. On the other hand, BSi and BSi + G groups showed an important cellular reaction and granulation/fibrous tissue formation from the first to the last period of observation. Runx-2 and VEGF immunolabeling were coherent with this result. However, histomorphometry did not reveal significant differences considering new bone formation. CONCLUSIONS: Reconstructed maxillary sinuses using Biosilicate® permitted satisfactory new bone formation in comparison to the deproteinized bovine bone and AG. However, the presence of granulation/fibrous tissue and inflammatory cells associated to the degrading biomaterial indicate that further studies should be careful performed considering the immunological aspect of this new biomaterial.

Incorporation of collagen and PLGA in bioactive glass: in vivo biological evaluation.

Bioactive glasses (BG) are known for their unique ability to bond to bone tissue. However, in critical situations, even the osteogenic properties of BG may be not sufficient to produce bone consolidation. The use of composite materials may constitute an optimized therapeutical intervention for bone stimulation. The aim of this study was to characterize BG/collagen/poly (d,l-lactic-co-glycolic) acid (BG/COL/PLGA) composites, in vitro biocompatibility and in vivo biological properties. MC3T3-E1 cells were evaluated by cell proliferation, ALP activity, cell adhesion and morphology. Qualitative histology and immunohistochemistry were performed in a calvarial bone defect model in rats. The in vitro study demonstrated, after 3 and 6 days of culture, a significant increase of proliferation was observed for BG/PLGA compared to BG/COL and BG/COL/PLGA. BG/COL/PLGA presented a higher value for ALP activity after 3 days of culture compared to BG/PLGA. For in vivo analysis, 6 weeks post-surgery, BG/PLGA showed a more mature neoformed bone tissue. As a conclusion, the in vitro and in vivo studies pointed out that BG/PLGA samples improved biological properties in calvarial bone defects, highlighting the potential of BG/PLGA composites to be used as a bone graft for bone regeneration applications.

Physico-chemical characterization and biocompatibility of hydroxyapatite derived from fish waste.

The aim of this study was to synthesize hydroxyapatite (HAP) powder from fish waste. The powder was characterized through X-ray diffraction, Fourier transform infrared spectroscopy, ion exchange chromatography, scanning electron microscopy and plasma emission spectrometry. The cyto- and genotoxicity was carried out to demonstrate biocompatibility in vivo by means of rat subcutaneous tissue test. The results showed that the visible crystalline nature of typical apatite crystal structure when they were calcined at 800 °C. Infrared spectroscopy analysis showed similar composition to HAP standard with the presence of carbonate ion demonstrated by wave number values of 871 cm-1 and 1420 cm-1 for calcinations at 800 °C. The scanning electronmicrographies depicted the crystal morphology and porous nature with average pore size of ~10 µm. Plasma emission spectrometry and ion exchange chromatography confirmed the presence of Ca and P in the samples. The mean of calcium content was 36.8; Mg was 0.8, Na was 0.7 and K was 0.5. Rat subcutaneous tissue test revealed that HAP presented biocompatibility. Furthermore, the lack of cyto- and genotoxicity in blood, liver, kidney and lung were noticed after 30 days of HAP implantation. Taken together, our results demonstrated that HAP from fish waste exhibits a great potential for using as biomaterial since is represents a simple, effective, low-cost process and satisfactory degree of biocompatibility.

The use of micronucleus assay in exfoliated oral cells in patients undergoing fixed orthodontic therapy: a systematic review with meta-analysis

Abstract The aim of this systematic review was to evaluate published papers regarding the micronucleus assay in oral mucosal cells of patients undergoing orthodontic therapy (OT). A search of the scientific literature was made in the PubMed, Scopus, and Web of Science databases for all data published until November, 2021 using the combination of the following keywords: "fixed orthodontic therapy," "genetic damage", "DNA damage," "genotoxicity", "mutagenicity", "buccal cells", "oral mucosa cells," and "micronucleus assay". The systematic review was designed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Nine studies were retrieved. Some authors demonstrated that OT induces cytogenetic damage in oral mucosal cells. Out of the nine studies included, two were classified as strong, five as moderate, and two as weak, according to the quality assessment components of the Effective Public Health Practice Project (EPHPP). Meta-analysis data revealed no relationship between mutagenicity in oral cells and OT in different months of treatment. At one month, the SMD = 0.65 and p = 0.08; after three months of OT, the SMD = 1.21 and p = 0.07; and after six months of OT, the SMD = 0.56 and p = 0.11. In the analyzed months of OT, I2 values were >75%, indicating high heterogeneity. In summary, this review was not able to demonstrate that OT induces genetic damage in oral cells. The study is important for the protection of patients undergoing fixed OT, given that mutagenesis participates in the multi-step process of carcinogenesis.