Influence of Different Porosities of Titanium Meshes on Bone Neoformation: Pre-Clinical Animal Study with Microtomographic and Histomorphometric Evaluation.

The aim of this study was to evaluate the influence of different types of porosity of titanium meshes on the bone neoformation process in critical defects surgically created in rat calvaria, by means of microtomographic and histomorphometric analyses. Defects of 5 mm in diameter were created in the calvaria of 36 rats, and the animals were randomly treated and divided into the following groups (6 animals per group): NCOG (negative control, only blood clot), TEMG (Polytetrafluoroethylene-PTFE-membrane), SPTMG (small pore titanium mesh), SPMMG (small pore mesh + PTFE), LPTMG (large pore titanium mesh), and LPMMG (large pore mesh + PTFE). After 60 days, the animals were sacrificed, and the bone tissue formed was evaluated with micro-CT and histomorphometry. The data were compared using an ANOVA followed by the Tukey post-test (p ≤ 0.05). The microtomographic results showed that the SPTMG group presented the highest numerical value for bone volume/total volume (22.24 ± 8.97), with statistically significant differences for all the other groups except LPTMG. Considering the histomorphometric evaluation, groups with only porous titanium meshes showed higher values compared to the groups that used the PTFE membrane and the negative control. The SPTMG group presented higher values in the parameters of area (0.44 mm2 ± 0.06), extension (1.19 mm2 ± 0.12), and percentage (7.56 ± 1.45%) of neoformed bone. It was concluded that titanium mesh with smaller pores showed better results and that the association of PTFE membranes with titanium meshes did not improve the outcomes, suggesting a correlation between mesh porosity and underlying bone repair.

Evaluation of Implant Surface Modification with Nanohydroxyapatite Associated with the Use of L-PRF: In Vivo Study in Rats.

Leukocyte-platelet-rich fibrin (L-PRF) contains growth factors that stimulate bone regeneration. This study evaluated the bone repair in a tibia rat model around two implant surfaces in combination or not with L-PRF by assessing microtomographic and histomorphometric parameters. A total of 48 female rats were used in the study, in which 24 received implants with two types of surface treatments (dual acid etched-DAE or nanohydroxyapatite-nanoHA), and the other 24 received the same mini implants with L-PRF, which was collected by cardiac puncture, centrifugated, and inserted in the bone bed. The animals were euthanized 7 and 30 days after implant placement, and the retrieved samples were prepared for microtomographic and histomorphometric (bone-to-implant contact-BIC; and Bone Area Fraction Occupancy-BAFO) analyses. The adhesion of the nanoHA surface onto the implant surface was investigated by insertion and removal in simulated bone medium (Sawbones). The adhesion evaluation revealed that the loss of nanoHA after this procedure (as measured with SEM) from the implant surface was less than 1%. Overall, the nanoHA surface presented more bone in contact and in proximity to the implant, a higher bone surface/tissue volume fraction, a higher number of bone trabeculae, as well as trabecular separation relative to the DAE surface. Such results were more evident when the nanoHA surface was combined with L-PRF and after 30 days in vivo. The nanoHA surface presented higher BAFO when compared to DAE, with or without association with L-PRF. Therefore, implants with a nanoHA surface potentially benefit from the association to L-PRF.

The Effect of Proton Pump Inhibitors on Early Implant Failure A Retrospective Cohort Study.

Background and Objectives: Maintenance of a firm and long-term stable osseointegration is the primary goal of implant dentistry. Time is used to define implant failure characteristics. Early implant failure (EIF) occurs up to one year after loading. Recent studies indicated an association between proton pump inhibitors (PPI) therapy and failure of osseointegration. The present study assessed whether the use of PPIs is a risk factor to EIF. Materials and methods: A retrospective cohort study including 687 patients and 2971 dental implants. The study group (PPIs users) comprised 17.3% (119) individuals and 18.7% (555) implants. The remaining cohort (82.7% (568) individuals and 81.3% (2416) implants) served as control. The information was taken from the patients' files. The following information was collected: age, gender, physical status, systemic diseases, HbA1C values before and after implant-supported prosthesis delivery in cases of diabetes mellitus, smoking, implant location, number of implants per individual, bone augmentation, implant brand, length and width, and EIF. EIF was defined as implant removal within a period of up to 12 months from loading. Results: EIF in PPIs vs. non-PPIs users was 19.3% vs. 14.3% (p = 0.16) at patient level and 5.4% vs. 3.5% at implant level (p = 0.03). Univariate analysis yielded factors significantly associated with PPIs use, including older age, physical status of the American Society of Anesthesiology (ASA) 3, hypertension, hyperlipidemia, diabetes mellitus, osteoporosis, cardiovascular accident (CVA), location (anterior mandible), shorter and narrower implants, and higher number of implants per individual. Multivariate analysis yielded statistically significant OR of 1.91; p = 0.01 for EIF following PPIs use and 2.3; p < 0.001 for location in anterior mandible. Conclusions: Patients and their healthcare providers are advised to carefully consider the potential risks of taking PPIs prior to dental implant surgery. Further research is needed to confirm these risks and elucidate systemic and local factors that may be involved in such outcomes.

Effect of Smoke Exposure on Gene Expression in Bone Healing around Implants Coated with Nanohydroxyapatite.

This study evaluated the effect of smoke exposure on the expression of genes related to bone metabolism in implants coated with nanohydroxyapatite (NHA). A total of 36 rats were exposed to cigarette smoke for 60 days. The animals were allocated into three groups: machined implants (MAC), dual acid-etched implants (DAE), and NHA-coated implants (NHA). Implants were installed in the left tibia of the rats after 30 days of smoke exposure. The implants were retrieved 7 and 30 days after implantation, and the adjacent bone analyzed using a real-time polymerase chain reaction for gene expression of alkaline phosphatase (ALP), osteopontin (OPN), receptor activator of the nuclear factor kappa ligand (RANKL), osteoprotegerin (OPG), the RANKL/OPG ratio, osteocalcin (OCN) and runt-related transcription factor 2 (Runx2). After 7 days, Runx2, OPN and OPG expression demonstrated significantly higher levels for the NHA surface treatment relative to DAE and MAC surfaces. NHA presented the lowest RANKL and RANKL/OPG levels. After 30 days, NHA-coated implants showed significantly higher levels of Runx2, ALP, OPN, OPG, OC, RANKL and RANKL/OPG relative to DAE and MAC implants. The results indicated a greater osteogenic and high osteoclastic activity around NHA implants, in comparison to DAE and MAC implants.

Evaluation of a New Porcine Bone Graft on the Repair of Surgically Created Critical Bone Defects in Rat Calvaria: Histomorphometric and Microtomographic Study.

The aim of this study was to evaluate the use of a new porcine bone graft in rat calvaria bone defects. Critical defects were surgically created in 24 rats that were divided into four experimental groups according to defect filling (n = 6): Control Group (CG)­blood clot; Porcine Bone Group (PG)­porcine-derived bone substitute; (BG): Bio-Oss Group (BG)−chemically and heat-treated bovine graft; Bonefill Group (BFG)­chemically treated bovine bone substitute. Euthanasia of the animals occurred 30 days after the surgery, and the area of the original surgical defect and the surrounding tissues were removed for micro-CT and histomorphometric analysis. In the micro-CT evaluation, the PG presented statistically significant differences (p < 0.05) in comparison to the CG, BG and BFG, for the parameters percentage of Bone Volume (BV/TV), Surface Bone Density (BS/TV), Number of Trabeculae (Tb.N) and Bone Connectivity (Conn), but not for Total Porosity (Po.tot) and Trabecular Thickness (Tb.Th). The histomorphometric analysis showed that the PG presented similar results to the BG regarding newly formed bone extension and to the BG and BFG regarding newly formed bone area. The porcine-derived graft presented superior microtomographic and histomorphometric results when compared to the two bovine bone substitutes.

In vitro antimicrobial effect of titanium anodization on complex multispecies subgingival biofilm.

Anodization is a routine industrial galvanic method that produces a titanium oxide layer on the surface of titanium. Considering the possibility that this technique could influence microbial adsorption and colonization, this in vitro study was conducted to evaluate the impact of a process of anodization applied to a titanium surface on the microbial profile of multispecies subgingival biofilm. Titanium discs produced by using two different processes-conventional and Anodization-were divided into two groups: conventional titanium discs with machined surface (cpTi) Control Group and titanium discs with anodic oxidation treatment (anTi) Test Group. Subgingival biofilm composed of 33 species was formed on the titanium discs that were positioned vertically in 96-well plates, for 7 days. The proportions and the counts of microbial species were determined using a DNA-DNA hybridization technique, and data were evaluated using Mann-Whitney test (p < 0.05). Mean total bacterial counts were lower in Test Group in comparison with Control Group (p < 0.05). Nine bacterial species differed significantly, and were found in higher levels in Control Group in comparison with Test Group, including T. forsythia, E. nodatum, and F. periodonticum. In conclusion, titanium discs with anodization could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm the clinical impact of these findings.

The Effect of Antimicrobial Photodynamic Therapy in the Osseointegration of Immediately Placed Implants in Sites with Ligature-Induced Periodontitis in Dogs.

This study evaluated the effect of the antimicrobial photodynamic therapy (aPDT) on the osseointegration of immediate implants in a healing situation with greater challenges. The mandibular premolars of eight beagle dogs were submitted to ligature-induced periodontal disease. After 3 months, teeth were extracted and immediate implants were placed in the sockets previously decontaminated by mechanical debridement (MD) or MD+aPDT. Following 12 weeks, the dogs were euthanized and the specimens were analyzed. Histologic and histomorphometric analyses demonstrated significantly better results for the immediate implants decontaminated by debridement associated with aPDT. The sites treated with MD+aPDT led to osseointegration of the immediate implants without evidence of inflammation; conversely, evidence of peri-implantitis was observed where aPDT was not used.

Arterial hypertension perpetuates alveolar bone loss.

Few studies have focused on the impact of hypertension on the progression of periodontitis (PD). The purpose of this study was to evaluate whether hypertension affects PD by enhancing bone loss even after the stimulus for PD induction is removed. Ligature-induced PD was created on the first mandibular molars of spontaneously hypertensive rats (SHR) and normotensive rats (Wistar Kyoto-WKY). The animals were assigned to non-ligated controls (C) and PD groups: WKY-C, WKY-PD, SHR-C, and SHR-PD. After 10 days, five animals of each group were killed and the ligatures of the other animals were removed. On the 21st day (11 days without PD induced), the remaining animals were killed. The jaws were defleshed and the amount of bone loss was measured. After 10 days, the PD groups showed more bone loss than its controls (P < .05); SHR-PD = 0.72 ± 0.05 mm, SHR-C = 0.39 ± 0.04 mm, WKY-PD = 0.75 ± 0.04 mm, and WKY-C = 0.56 ± 0.04 mm. The cumulative bone loss on day 21 (0.94 ± 0.13 mm) was significantly worse than on day 10 only in SHR-PD group (P < .05). The final bone loss differences between PD and C groups accounted for 102% (SHR) and 26% (WKY) increase in comparison with the initial control levels. Hypertension is associated with progressive alveolar bone loss even when the stimulus for PD induction is removed and it may be speculated that host condition perpetuates alveolar bone loss.

Acellular dermal matrix graft with or without enamel matrix derivative for root coverage in smokers: a randomized clinical study.

AIM: The aim of this randomized controlled clinical study was to compare the use of an acellular dermal matrix graft (ADMG) with or without the enamel matrix derivative (EMD) in smokers to evaluate which procedure would provide better root coverage. MATERIAL AND METHODS: Nineteen smokers with bilateral Miller Class I or II gingival recessions ≥3 mm were selected. The test group was treated with an association of ADMG and EMD, and the control group with ADMG alone. Probing depth, relative clinical attachment level, gingival recession height, gingival recession width, keratinized tissue width and keratinized tissue thickness were evaluated before the surgeries and after 6 months. Wilcoxon test was used for the statistical analysis at significance level of 5%. RESULTS: No significant differences were found between groups in all parameters at baseline. The mean gain recession height between baseline and 6 months and the complete root coverage favored the test group (p = 0.042, p = 0.019 respectively). CONCLUSION: Smoking may negatively affect the results achieved through periodontal plastic procedures; however, the association of ADMG and EMD is beneficial in the root coverage of gingival recessions in smokers, 6 months after the surgery.

Antimicrobial photodynamic therapy in the non-surgical treatment of aggressive periodontitis: cytokine profile in gingival crevicular fluid, preliminary results.

BACKGROUND: Aggressive periodontitis is a specific form of periodontal disease that is characterized by rapid attachment loss and bone destruction. Cytokine profiles are of considerable value when studying disease course during treatment. The aim of this trial was to investigate cytokine levels in the gingival crevicular fluid (GCF) of patients with aggressive periodontitis, after treatment with photodynamic therapy (PDT) or scaling and root planing (SRP), in a split-mouth design on -7, 0, +1, +7, +30, and +90 days. METHODS: Ten patients were randomly treated with PDT using a laser source associated with a photosensitizer or SRP with hand instruments. GCF samples were collected, and the concentrations of tumor necrosis factor-alpha (TNF-alpha) and receptor activator of nuclear factor-kappa B ligand (RANKL) were determined by enzyme-linked immunosorbent assays. The data were analyzed using generalized estimating equations to test the associations among treatments, evaluated parameters, and experimental times (alpha = 0.05). RESULTS: Non-surgical periodontal treatment with PDT or SRP led to statistically significant reductions in TNF-alpha level 30 days following treatment. There were similar levels of TNF-alpha and RANKL at the different time points in both groups, with no statistically significant differences. CONCLUSION: SRP and PDT had similar effects on crevicular TNF-alpha and RANKL levels in patients with aggressive periodontitis.

Immune Cells Depletion During Wound Healing as a Long-Term Effect of Undernutrition / Depleción de Células Inmunocitarias Durante la Curación de una Herida como Efecto de Desnutrición Postnatal

Undernutrition in early life is associated with a number of acute and chronic sequelae, and recovering is a controversial issue. Even if undernutrition in Brazil is declining, studies have shown that about 31% of brazilian children still present severe or moderate malnutrition. The present study goal was to induce early malnutrition in rats and observe short- (undernourished) and long-term (after recovered) effects on defense cells involved in wound healing. Undernutrition was produced by separating the pups from the mother for 10 hours/day during the suckling period (21 days after birth). As controls were used rats at same age not submitted to suckling restriction. Undernutrition and recovering states were assessed by body weight. Skin wounds were made on the shaved backs of all, undernourished, recovered and their controls, under tribromoethanol anesthesia. Aninals were sacrificed 1, 3, 7 and 14 days after surgery and the tissues were properly prepared and observed under light microscopy. Our results showed that: 1) neutrophils, lymphocytes and macrophages couting in healing area were lower in undernourished and in recovered animals as compared with their controls; 2) there were a basal deficiency in lymphocytes and macrophages numbers in recovered animals but not in those acutelly undernourished. These results allow us to conclude that post-nattally undernourished animals submitted to a nutritional rescue time showed a complete recovery in physical weight, but in spite of the physical recovery, the wound healing showed less defense cell density in healing areas suggesting long-term sequelae of early undernutrition.

La desnutrición postnatal está asociada a un conjunto de secuelas agudas y crónicas, y su recuperación es aún asunto controvertido. En Brasil, a pesar de estar disminuyendo la desnutrición, algunos estudios han demostrado que alrededor del 31% de los niños presentan malnutrición moderada o severa. El objetivo del presente estudio fue inducir una desnutrición precoz en ratas y observar los efectos inmediatos (desnutrición) y permanentes (depués de la recuperación) sobre las células de defensa involucradas en la cicatrización. La desnutrición fue provocada separando las crías de sus madres, por 10 horas diarias, durante el periodo de lactancia (21 días de nacidos). Como contoles fueron usadas ratas de la misma edad no sometidas a restrición láctea. Los estados de desnutrición y de recuperación fueron evaluados por el peso corporal. Las heridas fueron realizadas en la piel rasurada del dorso de los animales desnutridos, recuperados y controles, bajo anestesia con tribromoetanol. Los animales fueron sacrificados 1, 3, 7 y 14 días después de la cirugía y los tejidos de la región cicatricial fueron procesados histológicamente y examinados al microscopio óptico. Los resultados mostraron que: 1) el número de neutrófilos, linfocitos y macrófagos en la área de cicatrización, fue menor en los animales desnutridos y en recuperación que en los controles; 2) enlos animales recuperados hubo una deficiencia basal en el número de linfocitos y macrófagos, lo que no ocurrió en los animales con desnutrición aguda. Estos resultados permitieron concluir que los animales sometidos a desnutrición postnatal mostraron una recuperación completa en el peso físico después del periodo de recuperación nutricional, pero que la región de cicatrización mostró menor densidad de células de defensa, sugiriendo secuelas permanentes de la desnutrición postnatal.