Hydrophilic titanium surface modulates early stages of osseointegration in osteoporosis.

OBJECTIVE: Using a mouse osteoporotic model, this study aimed to determine the influence of hydrophilic titanium surfaces on gene expression and bone formation during the osseointegration process. BACKGROUND: Based on the previous evidence, it is plausible to assume that osteoporotic bone has a different potential of bone healing. Therefore, implant surface modification study that aims at enhancing bone formation to further improve short- and long-term clinical outcomes in osteoporosis is necessary. MATERIAL AND METHODS: Fifty female, 3-month-old mice were included in this study. Osteoporosis was induced by ovariectomy (OVX, test group) in 25 mice. The further 25 mice had ovaries exposed but not removed (SHAM, control group). Seven weeks following the ovariectomy procedures, one customized implant (0.7 × 8 mm) of each surface was placed in each femur for both groups. Implants had either a hydrophobic surface (SAE) or a hydrophilic treatment surface (SAE-HD). Calcium (Ca) and phosphorus (P) content was measured by energy-dispersive X-ray spectroscopy (EDS) after 7 days. The femurs were analyzed for bone-to-implant contact (BIC) and bone volume fraction (BV) by nano-computed tomography (nano-CT) after 14 and 28 days. Same specimens were further submitted to histological analysis. Additionally, after 3 and 7 days, implants were removed and cells were collected around the implant to access gene expression profile of key osteogenic (Runx2, Alp, Sp7, Bsp, Sost, Ocn) and inflammatory genes (IL-1ß, IL-10, Tnf-α, and Nos2) by qRT-PCR assay. Statistical analysis was performed by ANOVA and paired t test with significance at P < .05. RESULTS: The amount of Ca and P deposited on the surface due to the mineralization process was higher for SAE-HD compared to SAE on the intra-group analysis. Nano-CT and histology revealed more BV and BIC for SAE-HD in SHAM and OVX groups compared to SAE. Analysis in OVX group showed that most genes (ie, ALP, Runx2) involved in the bone morphogenetic protein (BMP) signaling were significantly activated in the hydrophilic treatment. CONCLUSION: Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a faster response in terms of bone formation and osteogenic gene expression compared to SAE. Hydrophilic surface in situations of osteoporosis seems to provide additional benefits in the early stages of osseointegration.

Local Drug Delivery Systems in the Treatment of Periodontitis: A Literature Review.

In order to complement non-surgical therapy in periodontitis, there are multiple options of antimicrobials, such as metronidazole, chlorhexidine, minocycline, doxycycline and tetracycline, which can be locally delivered into the mucosa. These drugs are used in periodontal pockets and can inhibit or eliminate periodontopathogenic microorganisms as well as modulate the inflammatory response of tissues. However, limited data are available concerning the relationship between effect, efficacy and clinical status of the periodontium. This review aims to evaluate the effect and the efficacy of five types of local drug delivery systems in clinical parameters of periodontology. Researched papers using MEDLINE via PubMed, and LILACS databases related to five types of local drug delivery systems as chlorhexidine gluconate, doxycycline hyclate, metronidazole gel, minocycline ointment and tetracycline fibers, were reviewed aiming to address the mechanism of action and the evidence of clinical effectiveness of adjunctive use of these antimicrobials following surgical and/or non-surgical therapies. Inclusion criteria defined that articles must be randomized controlled trials performed in humans and published between 1996 and 2014. The adjunctive use of local drug delivery systems with controlled release properties may provide a defined, but limited, beneficial response on periodontal pockets. Furthermore, local drug delivery as an active treatment or maintenance therapy depends on clinical findings, responses to treatment described in the literature, desired clinical outcomes, and patients' dental and medical histories, including their past usage of antimicrobials.

The influence of interproximal contact on implant-supported fixed partial dentures in the posterior jaw: a photoelastic analysis.

The aim of this study was to analyze the effect of the separation of prosthetic crowns from fixed partial dentures by means of stress gradient evaluation. Three photoelastic models were created to examine contiguous implants with varying contact between the crowns (contact point [CP], contact surface [CS], splinted [SP]). The SP group presented the best results, followed by the CS group, indicating that the use of splinted prosthetic crowns and crowns with broad surface contacts is viable when considering the stress values.

Analysis In Vivo of Bone Modulation in Hydrophilic and Hydrophobic Titanium Implant Surfaces.

PURPOSE: To evaluate whether a hydrophilic surface treatment compared with a hydrophobic implant surface can enhance osseointegration by analysis of calcium deposition, bone-to-implant contact (BIC), bone volume (BV), and upregulation of genes involved in bone formation. MATERIALS AND METHODS: Sixty implants (n = 60) with a hydrophobic (SAE) or hydrophilic (SAE-HD) surface treatment were placed bilaterally in each femur of 3-month-old male mice (n = 30). Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were utilized for quantifying the presence of calcium on the implant surface 7 days after implant placement. The specimens were analyzed after 14 and 21 days for BIC and BV by Nano CT scanning followed by histologic evaluation. Additionally, 1, 3, and 7 days postsurgery, femurs were harvested, implants were explanted, and gene expression (Sp7, Bsp, Sost, IL-1α, and IL-10) by quantitative real-time polymerase chain reaction was studied. Moreover, implants were characterized for surface roughness area. Data were statistically analyzed with two-way analysis of variance (ANOVA) followed by the Tukey test (P < .05). RESULTS: The amount of calcium on the surface was higher for SAE-HD after 7 days. Nano CT revealed significantly more BV in the SAE-HD than the SAE surface. The histologic assessment showed increased BIC in SAE-HD in comparison to SAE. SAEHD showed significantly increased levels of genes involved in bone formation. CONCLUSION: Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a better response compared with SAE.

Histologic analysis of the oral mucosa lining osseointegrated implant cover screws: a study in humans.

Osseointegrated dental implants are inserted into the alveolar ridge, and for them to function as tooth replacements, the surrounding tissues need to adapt to them. Just as with teeth, dental implants traverse the oral mucosa and have access to the contaminated environment of the oral cavity. Therefore, periodontal and peri-implant tissues are important for establishing a protective barrier. The aim of the present study was to perform a histologic analysis of the mucosa surrounding osseointegrated implant cover screws. For this study, 17 mucosal specimens were obtained from 12 patients during the second surgical session for implant exposure to the oral environment. After histologic preparation, specimens were sectioned perpendicularly to the mucosal surface to a thickness of about 3 microm, stained with 1% toluidine blue, and examined under light microscopy. All specimens showed a keratinized, stratified, squamous epithelium with well-defined strata. In the lamina propria, unorganized dense connective tissue was noted in the reticular layer, and in 4 samples, a chronic inflammatory infiltrate was seen in this region. The papillary layer presented tall connective papillae consisting of loose connective tissue. The results of this study confirm the hypothesis that the mucosa that conceals osseointegrated implant cover screws has the same morphologic characteristics as the alveolar masticatory mucosa. Furthermore, clinical conditions of normality in peri-implant tissues may not coincide with situations of histologic normality.

Biocompatibility of three bioabsorbable membranes assessed in FGH fibroblasts and human osteoblast like cells culture.

OBJECTIVES: Specific physical and chemical features of the membranes may influence the healing of periodontal tissues after guided tissue regeneration (GTR). The aim of the present investigation was to analyze the biological effects of three bioabsorbable membranes. The hypothesis is that all tested membranes present similar biological effects. METHODS: Human osteoblast like-cells (SaOs-2) and gingival fibroblasts FGH (BCRJ -RJ) were cultured in DMEM medium. The viability of the cells cultured on the membranes was assesses using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Quantitative determination of activated human Transforming Growth Factor beta 1 (TGF-ß1) on the supernatants of the cell culture was observed. Samples were examined using scanning electron microscope (SEM). RESULTS: SaOs2, in 24 hours, PLA group showed higher values when compared to other groups (P < 0.05). All groups presented statistical significance values when compared two times. In 4 h and 24 h, for the fibroblasts group, significantly difference was found to PLA membrane, when compared with the other groups (p < 0.05). For TGFß1 analyzes, comparing 4 and 24 h, for the osteoblast supernatant, COL1 and PLA groups showed statistically significant difference (p <0,008). On the analysis of culture supernatants of fibroblasts, in 24 hours, only PLA group presented significant difference (p = 0,008). CONCLUSIONS: The biomaterials analyzed did not show cytotoxicity, since no membrane presented lower results than the control group. PLA membrane presented the best performance due to its higher cell viability and absorbance levels of proliferation. Both collagen membranes showed similar results either when compared to each other or to the control group.

Effects of platelet-rich plasma on healing of alveolar socket: split-mouth histological and histometric evaluation in Cebus apella monkeys.

CONTEXT: The prediction of implant treatment is directly influenced by the quality of the remaining bone after tooth extraction. AIMS: The purpose of this experimental study was to, histologically and histometrically, evaluate the bone repair process in the central areas of extraction sockets filled with platelet-rich plasma. MATERIALS AND METHODS: Four young adult male Cebus apella monkeys were used. The extraction of both right and left inferior second premolars was accomplished. After extraction, in one of the extraction sockets, coagulum was maintained while in the other it was removed; the alveolus was dried with gauze compress and filled up with platelet concentrate. For PRP production, Sonnleitner's protocol was followed. The specimens for histological and histometric assessment were obtained in 30, 90, 120 and 180 days intervals. RESULTS: In 30 days new bone formation was intense in both experimental and control sockets and no significant differences were observed between the two groups. After 90 days of the extraction, while the control group showed signs of decrease in osteogenesis, in the experimental unit, the process of bone formation and fibroblast-like cell proliferation remained intense. After 120 days, the PRP treated socket was occupied by large trabeculae of bone. After 180 days, the control unit was occupied mostly with bone marrow. The experimental unit remained occupied with large amounts of bone tissue. CONCLUSIONS: It was possible to conclude that bone repair was enhanced by the use of platelet- rich plasma in alveolar sockets.

Effect of absorbent tetracycline-loaded membrane used in the reduction of periodontal pockets: an in vivo study.

This clinical study evaluated the influence of scaling and root planning (SRP), with and without the use of tetracycline-loaded bovine absorbent membrane, in the reduction of periodontal pockets according to 3 parameters: probing pocket depth (PPD), bleeding on probing (BOP) and plaque index (PI). Twenty-four patients were selected totalizing 144 random teeth divided in 2 groups (n=72 teeth) - control (SRP) and experimental (SRP with tetracycline-loaded absorbent membrane). PPD, BOP and PI were determined before and 28 days after the treatment. In all patients, the PPD values at the end of the treatment were always lower than the baseline values. There was a reduction of the PI for both treatments, but it was more evident on the experimental group. In conclusion, the use of tetracycline-loaded absorbent membrane could result in a better prognosis compared to scaling and root planning after only 28 days of evaluation.