Search

Background: Mucointegration seems to gain interest when talking about success in the maintenance of dental implants. As we well know, collagen fibres cannot be inserted due to the lack of root structure on the implant surface, so the structural integration of peri-implant tissues that provide a firm seal around implants seems to be of interest when it comes to ensuring the survival of dental implants. To achieve a good epithelial barrier, the physicochemical characteristics of the surfaces of the restorative materials are of vital importance; therefore, the objective of this study is to analyse the histological behaviour of the peri-implant soft tissues in three different restorative materials. Methods: Histological analysis of biopsied peri-implant keratinised mucosa, inflammatory epithelium and connective tissue in contact with a reinforced composite (BRILLIANT Crios), a cross-linked polymethylmethacrylate (TELIO CAD), and a hybrid ceramic (Vita Enamic), restored on a customised Atlantis-type abutment (Dentsply Sirona) between 60 and 180 days after restoration. Results: A greater number of cells per mm2 of keratinised epithelium is observed in the reinforced composite, which could indicate greater surface roughness with greater inflammatory response. In this way, the greater number of lymphocytes and the lateral cellular composition of the inflammatory cells confirm the greater inflammatory activity towards that material. The best material to rehabilitate was hybrid ceramic, as it shows a better cellular response. Conclusions: Knowing the limitations of the proposed study, despite the fact that greater inflammation is observed in the reinforced composite relative to the other materials studied, no statistically significant differences were found.

[Background] On certain occasions, oral cancer is preceded by potentially malignant lesions. The degree of dysplasia in Guinea pigs attempts to determine the risk of developing a malignant lesion. The search for genetic mutations, biomarkers, as a more truthful and reproducible diagnostic tool, tries to fill the gaps in the anatomopathological study. In this line, the present retrospective case-control study is based on the detection of known mutations of the NOTCH1 gene in biopsied samples of potentially malignant lesions from 22 patients who attend the Oral and Maxillofacial Surgery service of the Virgen del Rocío University Hospital., [Material and methods] DNA extraction after dewaxing of the samples using the Minikit QIAamp DNA FFPE tissue extraction kit with extraction kit (reference 56404) of QIAGEN. Subsequently, with the DNA obtained, 4 amplification reactions were carried out using enzyme polymerase. Before sequencing the samples, they were purified with the ExoSAP-IT for PCR product cleaning kit of the INVITROGEN brand. Finally, to detect somatic mutations in NOTCH1, TaqMan Mutation Detection Assays was used and for the analysis of mutations we worked with the Mutation Detector software., [Results] The mutation for NOTCH1 is not detected, the studied sample does not present the mutation, or it is below the limits of detection of the software., [Conclusions] In the clinical setting of the sample, the NOTCH1 mutation seems to be not very frequent, although NOTCH1 has been described as a gene related to oral cancer in other geographical settings.

Down syndrome patients show success rates in dental implants much lower than those observed in the general population. This retrospective case-control study aimed to identify possible genes that are related to the regulation of inflammatory responses and bone metabolism related to periimplantitis and implant loss, as well as genes related to bone quality. This process involved using the functional analysis of the gene expression software Transcriptome Analysis Console (TAC version 4.0 Applied BiosystemsTM, Thermo Fisher Scientific, Waltham, MA, USA) and a search for possible candidate genes involved. The focus was placed on the 93 genes related to periodontitis, periimplantitis, bone loss, implant loss, and genes related to bone quality and regulators underlying the establishment and maintenance of osseointegration. Five genes showed statistically significant results (p < 0.05) in our comparison. Four of them, IL1B (p = 0.023), IL1RN (p = 0.048), BGLAP (p = 0.0372) and PTK2 (p = 0.0075) were down-regulated in the periodontal disease and implant rejection group, and only one was overexpressed: FOXO1A (p = 0.0552). The genes with statistically significant alterations described in this article determine that the group of Down syndrome patients with periodontal disease and implant failure is a group of patients genetically susceptible to suffering from both conditions together.

(1) Background: Mucointegration seems to gain interest when talking about success in the maintenance of dental implants. As we well know, collagen fibres cannot be inserted due to the lack of root structure on the implant surface, so the structural integration of peri-implant tissues that provide a firm seal around implants seems to be of interest when it comes to ensuring the survival of dental implants. To achieve a good epithelial barrier, the physicochemical characteristics of the surfaces of the restorative materials are of vital importance; therefore, the objective of this study is to analyse the histological behaviour of the peri-implant soft tissues in three different restorative materials. (2) Methods: Histological analysis of biopsied peri-implant keratinised mucosa, inflammatory epithelium and connective tissue in contact with a reinforced composite (BRILLIANT Crios), a cross-linked polymethylmethacrylate (TELIO CAD), and a hybrid ceramic (Vita Enamic), restored on a customised Atlantis-type abutment (Dentsply Sirona) between 60 and 180 days after restoration. (3) Results: A greater number of cells per mm2 of keratinised epithelium is observed in the reinforced composite, which could indicate greater surface roughness with greater inflammatory response. In this way, the greater number of lymphocytes and the lateral cellular composition of the inflammatory cells confirm the greater inflammatory activity towards that material. The best material to rehabilitate was hybrid ceramic, as it shows a better cellular response. (4) Conclusions: Knowing the limitations of the proposed study, despite the fact that greater inflammation is observed in the reinforced composite relative to the other materials studied, no statistically significant differences were found.

Metallothioneins (MTs) are low molecular weight cysteine-rich proteins that can bind up to seven zinc ions. Among their numerous functions, MTs appear to act as protectors against oxidative and inflammatory injury. In our first published study, we reported downregulation of the isoforms MT1B (fold distance (FD) −2. 95; p = 0.0024), MT1F (FD −1.72; p = 0.0276), MT1X (FD −3.09; p = 0.0021 ), MT1H (FD −2.39; p = 0.0018), MT1M (FD −2.37; p = 0.0092), MT1L (FD −2. 55 ; p = 0.0048), MT1E (FD −2.71; p = 0.0014), MT2A (FD −2.35; p = 0.0072), MT1G (FD −2.24; p = 0.0118), and MT1A (FD −2.82; p = 0.0023) by comparing Down’s syndrome patients with periodontal disease and implant failure to those without periodontal disease and with a positive progression of their implants. In this gene validation study, we intended to verify the results of our first gene expression analysis. Materials and Methods: In our retrospective case–control study, we performed retrotranscription (RT-qPCR) of 11 RNA-to-cDNA samples using the SuperScript ™ VILO™ kit (50; reference 1,176,605) from Thermo Fisher. We conducted the study using the real-time PCR technique on the q-PCR ViiA 7 platform from Thermo Fisher. We chose the format of the Taqman Array Plate 16 Plus (reference 4,413,261) from Thermo Fisher, which accommodates 12 genes plus four controls (GAPDH, 18S, ACTB, and HPRT1). We conducted the analysis of the plates using the Thermo Fisher Cloud Web Software. Results: The results obtained through gene validation analysis show that in PD+RI+ patients, the genes encoding the isoforms MT1F (FD 0.3; p = 0.039), MT1X (FD 338; p = 0.0078), MT1E (FD 307; p = 0.0358 ), and MT2A (FD 252; p = 0.0428) continue to show downregulation, whereas MT1B (FD 2.75; p = 0.580), MT1H (FD 281; p = 0.152), MT1L (FD 354; p = 0.0965), and MT1G (FD 336; p = 0.0749) no longer show statistically significant results.

Our objective is to evaluate the regional regenerative potential of calvarial bone in critical- sized defects in a rabbit model using novel nanostructured silica-loaded membranes doped with zinc or doxycycline. Nanostructured membranes of (MMA)1-co-(HEMA)1/(MA)3-co-(HEA)2 loaded with 5 wt% of SiO2 nanoparticles (HOOC-Si-Membranes) were doped with zinc (Zn-HOOC-Si- Membrane) or doxycycline (Dox-HOOC-Si-Membrane). Critical bone defects were created on six New-Zealand-breed rabbit skulls and covered with the membranes. A sham defect without a membrane was used as the control. After six weeks, a histological analysis (toluidine blue technique) was employed to determine the area percentages of newly formed bone, osteoid bone, and soft tissue. The measurements were performed by dividing the total defect area into top (close to the membrane) and bottom (close to the dura mater) regions, or peripheral (adjacent to the old bone) and central (the sum of the remaining zones) regions. The peripheral regions of the defects showed higher osteogenic capacity than the central areas when the membranes were present. The proportion of new bone adjacent to the dura was similar to that adjacent to the membrane only when the HOOC-Si-Membranes and Zn-HOOC-Si-Membranes were used, indicating a direct osteoinductive effect of the membranes.

Metallothioneins (MTs) are low molecular weight cysteine-rich proteins that can bind up to seven zinc ions. Among their numerous functions, MTs appear to act as protectors against oxidative and inflammatory injury. In our first published study, we reported downregulation of the isoforms MT1B (fold distance (FD) -2. 95; p = 0.0024), MT1F (FD -1.72; p = 0.0276), MT1X (FD -3.09; p = 0.0021), MT1H (FD -2.39; p = 0.0018), MT1M (FD -2.37; p = 0.0092), MT1L (FD -2. 55; p = 0.0048), MT1E (FD -2.71; p = 0.0014), MT2A (FD -2.35; p = 0.0072), MT1G (FD -2.24; p = 0.0118), and MT1A (FD -2.82; p = 0.0023) by comparing Down's syndrome patients with periodontal disease and implant failure to those without periodontal disease and with a positive progression of their implants. In this gene validation study, we intended to verify the results of our first gene expression analysis. Materials and Methods: In our retrospective case-control study, we performed retrotranscription (RT-qPCR) of 11 RNA-to-cDNA samples using the SuperScript™ VILO™ kit (50; reference 1,176,605) from Thermo Fisher. We conducted the study using the real-time PCR technique on the q-PCR ViiA 7 platform from Thermo Fisher. We chose the format of the Taqman Array Plate 16 Plus (reference 4,413,261) from Thermo Fisher, which accommodates 12 genes plus four controls (GAPDH, 18S, ACTB, and HPRT1). We conducted the analysis of the plates using the Thermo Fisher Cloud Web Software. Results: The results obtained through gene validation analysis show that in PD+RI+ patients, the genes encoding the isoforms MT1F (FD 0.3; p = 0.039), MT1X (FD 338; p = 0.0078), MT1E (FD 307; p = 0.0358), and MT2A (FD 252; p = 0.0428) continue to show downregulation, whereas MT1B (FD 2.75; p = 0.580), MT1H (FD 281; p = 0.152), MT1L (FD 354; p = 0.0965), and MT1G (FD 336; p = 0.0749) no longer show statistically significant results.

(1) Background: The use of physical barriers to prevent the invasion of gingival and connective tissue cells into bone cavities during the healing process is called guided bone regeneration. The objective of this in-vitro study was to compare the growth of human osteoblasts on Poly(Lactic–co–Glycolic) (PLGA) membranes modified with oxygen plasma and Hydroxyapatite (HA), silicon dioxide (SiO2), and titanium dioxide (TiO2) composite nanoparticles, respectively. (2) Methods: All the membranes received a common treatment with oxygen plasma and were subsequently treated with HA nanostructured coatings (n = 10), SiO2 (n = 10) and TiO2 (n = 10), respectively and a PLGA control membrane (n = 10). The assays were performed using the human osteoblast line MG-63 acquired from the Center for Scientific Instrumentation (CIC) from the University of Granada. The cell adhesion and the viability of the osteoblasts were analyzed by means of light-field microphotographs of each condition with the inverted microscope Axio Observer A1 (Carl Zeiss). For the determination of the mitochondrial energy balance, the MitoProbe™ JC-1 Assay Kit was employed. For the determination of cell growth and the morphology of adherent osteoblasts, two techniques were employed: staining with phalloidin-TRITC and staining with DAPI. (3) Results: The modified membranes that show osteoblasts with a morphology more similar to the control osteoblasts follow the order: PLGA/PO2/HA > PLGA/PO2/SiO2 > PLGA/PO2/TiO2 > PLGA (p < 0.05). When analysing the cell viability, a higher percentage of viable cells bound to the membranes was observed as follows: PLGA/PO2/SiO2 > PLGA/PO2/HA > PLGA/PO2/TiO2 > PLGA (p < 0.05), with a better energy balance of the cells adhered to the membranes PLGA/PO2/HA and PLGA/PO2/SiO2. (4) Conclusion: The membrane in which osteoblasts show characteristics more similar to the control osteoblasts is the PLGA/PO2/HA, followed by the PLGA/PO2/SiO2.

The chemical composition and the surface characteristics of dental implants are factors that have a decisive effect on the osseointegration process. The surface characterization at the compositional and topographic level of three dental implants available in the market was performed with different surface treatments: (1) sandblasted and acid etched surface (SLA), (2) hydroxyapatite (HA) and tricalcium phosphate (TCP) blasted surface (HA/TCP), and (3) HA-blasted and non-etching acid washed surface (HA + AW). In addition, an in vitro viability study of MG-63 osteoblast cells was performed with a JC-1 test. To complete the study, an in vivo study was conducted in New Zealand rabbits. The study analyzed the histometric characteristics of the bone formed around the implants at the level of area, volume, bone density, accumulated bone density, and bone–implant contact (BIC). The rabbits were sacrificed at 6 weeks after implants were placed in the tibial metaphysis. No statistically significant differences were observed at the level of cell viability or histometric parameters between the different study groups (p > 0.05). SLA and HA/TCP surfaces were the ones that obtained a higher BIC value. Taking into account the limitations of this study, it can be concluded that the different implant surfaces analyzed favor a good bone response.

The main target of bone tissue engineering is to design biomaterials that support bone regeneration and vascularization. Nanostructured membranes of (MMA)1-co-(HEMA)1/(MA)3-co-(HEA)2 loaded with 5% wt of SiO2-nanoparticles (HOOC-Si-Membrane) were doped with zinc (Zn-HOOC-Si-Membrane) or doxycycline (Dox-HOOC-Si-Membrane). Critical bone defects were effectuated on six New Zealand-bred rabbit skulls and covered with the membranes. After six weeks, the bone architecture was evaluated with micro computed tomography. Three histological analyses were utilized to analyse bone regeneration, including von Kossa silver nitrate, toluidine blue and fluorescence. All membrane-treated defects exhibited higher number of osteocytes and bone perimeter than the control group without the membrane. Zn-HOOC-Si-Membranes induced higher new bone and osteoid area than those treated with HOOC-Si-Membranes, and control group, respectively. Zn-HOOC-Si-Membranes and Dox-HOOC-Si-Membranes attained the lowest ratio M1 macrophages/M2 macrophages. Dox-HOOC-Si-Membranes caused the lowest number of osteoclasts, and bone density. At the trabecular new bone, Zn-HOOC-Si-Membranes produced the highest angiogenesis, bone thickness, connectivity, junctions and branches. Zn-HOOC-Si-Membranes enhanced biological activity, attained a balanced remodeling, and achieved the greatest regenerative efficiency after osteogenesis and angiogenesis assessments. The bone-integrated Zn-HOOC-Si-Membranes can be considered as bioactive modulators provoking a M2 macrophages (pro-healing cells) increase, being a potential biomaterial for promoting bone repair.

Native collagen-based membranes are used to guide bone regeneration; but due to their rapid biodegradation, this treatment is often unpredictable. The purpose of this study was to investigate the biodegradability of natural collagen membranes. Three non-cross-linked resorbable collagen barrier membranes were tested: Derma Fina (porcine dermis), Evolution Standard (equine pericardium) and Duo-Teck (equine lyophilized collagen felt). 10 × 10 mm2 pieces of membranes were submitted to three different degradation procedures: (1) hydrolytic degradation in phosphate buffer solution, (2) enzyme resistance, using a 0.25% porcine trypsin solution, and (3) bacterial (Clostridium histolyticum) collagenase resistance test. Weight measurements were performed with an analytic microbalance. Thickness was measured with a digital caliper. Membranes were analyzed at different time-points, up to 21 d of immersion. A stereomicroscope was used to obtain membranes’ images. ANOVA and Student Newman Keuls were used for mean comparisons (p < 0.05), except when analyzing differences between time-points within the same membrane and solution where pair-wise comparisons were applied (p < 0.001). Derma Fina attained the highest resistance to all degradation challenges. Duo-Teck was the most susceptible membrane to degradation, complete degradation occurred as soon as 8 h. The bacterial collagenase solution performed as the most aggressive test as all membranes presented 100% degradation before 21 d.

Bruxism is an unconscious, involuntary and sustained motor activity that results in excessive teeth grinding or jaw clenching that could affect patients’ implants and rehabilitations. The aetiology for bruxism remains unknown, but it is known to involve multiple factors. The literature lacks studies on the possible effect of implant morphology on the resistance of the bone-implant osseointegrated interface when bruxism is present. Our objective is to assess the mechanical response of the bone-implant interface in bruxist patients whose implant prostheses are subjected to parafunctional cyclic loading over a simulated period of 10 years. A comparison was carried out between two implant types (M-12 and Astra Tech), and a pattern of bone loss was established considering both the stress state and the cortical bone surface loss as the evaluation criteria. Numerical simulation techniques based on the finite element analysis method were applied in a dynamic analysis of the received forces, together with a constitutive model of bone remodelling that alters the physical properties of the bone. The simulated cortical bone surface loss at the implant neck area was 8.6% greater in the Astra implant than in the M-12 implant. Compared to the M-12 implant, the higher sustained stress observed over time in the Astra implant, together with the greater cortical bone surface loss that occurred at its neck area, may be related to the major probability of failure of the prostheses placed over Astra implants in bruxist patients

[Background] Besides dental erosion syndrome, other oral syndromes could benefit from the stimulation of sali-vary secretion, in patients with gastro-oesophageal reflux disease (GORD). Our aims is evaluate the improvement of oral extra-oesophageal manifestations in patients with GORD using xylitol–malic acid tablets to stimulate salivary secretion., [Material and Methods] The effectiveness of salivary stimulation using xylitol–malic acid tablets (as a supplement to omeprazole 40 mg/day) was assessed in a clinical trial (n = 14) lasting six months with patients with prior posi-tive pH-metry, through GORD extra-oesophageal clinical signs, GerdQ and RDQ questionnaires, odontological variables, basal salivary secretion, stimulated salivary secretion, pH and buffer capacity, mucosal erythema index and dental wear. Statistics: chi-square (Haberman post-hoc), ANOVA, and Mann-Whitney U; variables between visits were evaluated with McNemar’s Student’s t and Wilcoxon tests; p < 0.05., [Results] 100% of patients not taking xylitol–malic acid presented xerostomia, but only 14.3% of patients taking xylitol–malic acid (p < 0.01) did. The mean saliva-buffer capacity at the last visit for patients not taking xylitol–malic acid was 2.14 ± 0.38, versus 2.71 ± 0.49 for patients taking xylitol–malic acid (p < 0.05). Retro-sternal burn-ing (p < 0.05), heartburn (p < 0.05) and regurgitation (p < 0.05) were also reduced., [Conclusions] Xylitol–malic acid tablets improve quality of life among patients with GORD, by reducing dry mouth, increasing saliva buffering and reducing heartburn, retro-sternal burning and regurgitation.

[Background] The aim of this in vitro study was to evaluate the effect of diode lasers at different wavelengths and power settings in handmade incisions in periodontal pockets and in oral mucosa of porcine tissue considering thermal damage, necrosis and the affected area of the soft tissue., [Material and Methods] Combining the following laser wavelengths, 445nm, 532nm (KTP), 810nm, 980nm, 1064nm and 1470nm, and a power range from 0.5W to 2.0W in a continuous wave mode (CW), we made hand-made incisions in porcine periodontal pockets and oral mucosa. After histological processing, we measured the area of lost tissue, the area of thermal damage and the area of necrosis. Then, we performed ANOVA to evaluate the difference between groups and two-way ANOVA to identify the influence of the laser-type variables and the power on the results., [Results] We applied an ANOVA test to evaluate the results, where statistical analysis showed clear differences between the 1470nm and 810nm laser groups that refer to thermal damage and necrosis in the periodontal pocket surface. Regarding the oral mucosa surface, the 1064nm laser showed differences in the analysis of lost tissue. According to the applied power, all the variables we studied (lost tissue area, area of thermal damage and necrosis) showed higher values when using a power of 2.0W instead of 0.5W., [Conclusions] According to our results, the 810nm diode laser for oral soft-tissue biopsy using power ranges be-tween 0.5W and 2W would be the best choice to avoid thermal damage in peri-incisional margins.

[Background] This study aims to evaluate whether the uptake difference by the condyles evaluated using single photon emission computed tomography (SPECT) examination is useful for predicting the activity of the feature and the advance of this pathology., [Material and Methods] An observational and prospective study has been carried out on nine patients affected by unilateral condylar hyperplasia (UCH) with complete bone maturation, with a follow-up over 18 months. At the beginning of the study, a test-battery was conducted including dental casts, articular examination, teleradiography and cephalometry, computed tomography and SPECT, creating two groups of patients from a difference in uptake between both condyles greater than 10% over the follow-up period. Evolution of data obtained with the rest of the diagnostic tests were compared to confirm UCH activity predicted by SPECT., [Results] The comparison of both groups did not show hardly any significant differences, with little clinical signifi-cance. Deviation of the mandibular line, the size of the branches or condyles behaved similarly in both study groups., [Conclusions] From the data obtained in our study, we can conclude that the use of the difference in uptake be-tween both condyles by applying the SPECT technique is not a valid approach for predicting clinical activity in cases of UCH.

The aim of our study is to evaluate different implant surface treatments using TiIV and TiV in in vitro and in vivo studies. An in vitro study was established comprising four study groups with treated and untreated TiIV titanium discs (TiIVT and TiIVNT) and treated and untreated TiV titanium discs (TiVT and TiVNT). The surface treatment consisted in a grit blasting treatment with alumina and double acid passivation to modify surface roughness. The surface chemical composition and the surface microstructure of the samples were analyzed. The titanium discs were subjected to cell cultures to determine cell adhesion and proliferation of osteoblasts on them. The in vivo study was carried out on the tibia of three New Zealand rabbits in which 18 implants divided into three experimental groups were placed (TiIVT, TiIVNT, and TiVT). Micro-computed tomography (micro-CT) was performed to determine bone density around the implants. The results showed that cell culture had minor adhesion and cell proliferation in TiIVT and TiVT within the first 6 and 24 h. However, no differences were found after 48 h. No statistically significant differences were found in the in vivo micro-CT and histological study; however, there was a positive trend in bone formation in the groups with a treated surface. Conclusions: All groups showed a similar response to in vitro cell proliferation cultures after 48 h. No statistically significant differences were found in the in vivo micro-CT and histological study.

Polymethyl methacrylate (PMMA) and lithium disilicate are widely used materials in the dental field. PMMA is mainly used for the manufacture of removable prostheses; however, with the incorporation of CAD-CAM technology, new applications have been introduced for this material, including as a provisional implant attachment. Lithium disilicate is considered the gold standard for definitive attachment material. On the other hand, PMMA has begun to be used in clinics as a provisional attachment until the placement of a definitive one occurs. Although there are clinical studies regarding its use, there are few studies on cell reorganization around this type of material. This is why we carried out an in vitro comparative study using discs of both materials in which human gingival fibroblasts (HGFs) were cultured. After processing them, we analyzed various cellular parameters (cell count, cytoskeleton length, core size and coverage area). We analyzed the surface of the discs together with their composition. The results obtained were mostly not statistically significant, which shows that the qualities of PMMA make it a suitable material as an implant attachment., Depto. de Odontología Conservadora y Prótesis, Fac. de Odontología, TRUE, pub

[Aim] Aware that Down Syndrome patients present among their clinical characteristics impaired immunity, the aim of this study is to identify the statistically significant differences in inflammation-related gene expression by comparing Down Syndrome patients with Periodontal Disease (DS+PD+) with Down Syndrome patients without Periodontal Disease (DS+PD-), and their relationship with periodontitis as a chronic oral inflammatory clinical feature., [Materials and Methods] Case study and controls on eleven Down Syndrome patients (DS+PD+ vs. DS+PD-). RNA was extracted from peripheral blood using a Qiagen PAXgene Blood miRNA Kit when performing an oral examination. A search for candidate genes (92 selected) was undertaken on the total genes obtained using a Scientific GeneChip® Scanner 3000 (Thermo Fisher Scientific) and Clariom S solutions for human, mouse, and rat chips, with more than 20,000 genes annotated for measuring expression levels., [Results] Of the 92 inflammation-related genes taken initially, four genes showed a differential expression across both groups with a value of <0.05 from the data obtained using RNA processing of the patient sample. Said genes were TNFSF13B (), ITGB2 (), ANXA3 (), and ANXA5 ()., [Conclusions] There are differences in inflammation-related gene expression in Down Syndrome patients when comparing patients who present a state of chronic oral inflammation with patients with negative rates of periodontal disease.

Background: Sometimes dental implants seem to be the only therapeutic alternative for the oral rehabilitation of patients with Down syndrome, given that they usually lose all their teeth early due to suffering aggressive periodontitis and they do not usually have the skills required to wear removable prostheses. However, the evolution of dental implants in these patients shows very adverse results. It is possible that basal genetic alterations, or at least some characteristics of these, may underlie these clinical results. The metabolic pathway of metallothioneins, molecules with an important influence on bone metabolism, could be one of the said alterations. Aims: To determine whether the expression of metallothioneins (MTs) and their metabolic pathway may be identified and related to the periodontitis and lack of osseointegration of dental implants in Down syndrome patients. Materials and Methods: Retrospective study of cases and controls by comparing patients with Down syndrome, periodontal disease, and implant failure (four patients, test group) with patients with Down syndrome, without periodontal disease, and without implant failure after two years of following (seven patients, control group), by extracting peripheral blood at the time of the dental examination to extract RNA and its subsequent processing in relation to gene expression of the metabolic pathway of metallothioneins. Results: The results identified low expression in the group of patients with periodontal disease and implant failure of genes MT1E, MT1H, MT1X, MT1A, MT1B, MT1C, MT1L, MT2A, MT1M, and MT1G. Conclusions: The low MT1 and MT2 gene expression seems to be related to the onset of periodontal disease and implant rejection in Down syndrome patients, although more data are required to confirm whether this relationship is due to one of the two conditions, to both independently, or to the two jointly—this last option being indicated by our current study.

[Aim] Titanium implants are commonly used as replacement therapy for lost teeth and much current research is focusing on the improvement of the chemical and physical properties of their surfaces in order to improve the osseointegration process. TiO2, when it is deposited in the form of pillar array nanometric structures, has photocatalytic properties and wet surface control, which, together with UV irradiation, provide it with superhydrophilic surfaces, which may be of interest for improving cell adhesion on the peri-implant surface. In this article, we address the influence of this type of surface treatment on type IV and type V titanium discs on their surface energy and cell growth on them., [Materials and methods] Samples from titanium rods used for making dental implants were used. There were two types of samples: grade IV and grade V. In turn, within each grade, two types of samples were differentiated: untreated and treated with sand blasting and subjected to double acid etching. Synthesis of the film consisting of titanium oxide pillar array structures was carried out using plasma-enhanced chemical vapor deposition equipment. The plasma was generated in a quartz vessel by an external SLAN-1 microwave source with a frequency of 2.45 GHz. Five specimens from each group were used (40 discs in total). On the surfaces to be studied, the following determinations were carried out: (a) X-ray photoelectron spectroscopy, (b) scanning electron microscopy, (c) energy dispersive X-ray spectroscopy, (d) profilometry, (e) contact angle measurement or surface wettability, (f) progression of contact angle on applying ultraviolet irradiation, and (g) a biocompatibility test and cytotoxicity with cell cultures., [Results] The application of ultraviolet light decreased the hydrophobicity of all the surfaces studied, although it did so to a greater extent on the surfaces with the studied modification applied, this being more evident in samples manufactured in grade V titanium. In samples made in grade IV titanium, this difference was less evident, and even in the sample manufactured with grade IV and SLA treatment, the application of the nanometric modification of the surface made the surface optically less active. Regarding cell growth, all the surfaces studied, grouped in relation to the presence or not of the nanometric treatment, showed similar growth., [Conclusions] Treatment of titanium oxide surfaces with ultraviolet irradiation made them change temporarily into superhydrophilic ones, which confirms that their biocompatibility could be improved in this way, or at least be maintained.

The novelty of this study is the addition of an ultrathin layer of nanostructured hydroxyapatite (HA) on oxygen plasma modified poly(lactic–co–glycolic) (PLGA) membranes (PO2) in order to evaluate the efficiency of this novel material in bone regeneration. Methods: Two groups of regenerative membranes were prepared: PLGA (control) and PLGA/PO2/HA (experimental). These membranes were subjected to cell cultures and then used to cover bone defects prepared on the skulls of eight experimental rabbits. Results: Cell morphology and adhesion of the osteoblasts to the membranes showed that the osteoblasts bound to PLGA were smaller and with a lower number of adhered cells than the osteoblasts bound to the PLGA/PO2/HA membrane (p < 0.05). The PLGA/PO2/HA membrane had a higher percentage of viable cells bound than the control membrane (p < 0.05). Both micro-CT and histological evaluation confirmed that PLGA/PO2/HA membranes enhance bone regeneration. A statistically significant difference in the percentage of osteoid area in relation to the total area between both groups was found. Conclusions: The incorporation of nanometric layers of nanostructured HA into PLGA membranes modified with PO2 might be considered for the regeneration of bone defects. PLGA/PO2/HA membranes promote higher osteosynthetic activity, new bone formation, and mineralisation than the PLGA control group.