Assessing bone formation on hydrophilic and hydrophobic implant surfaces in a murine model treated with bisphosphonates.

OBJECTIVE: To evaluate the osseointegration of implants with hydrophobic (HFB) and hydrophilic (HFL) surfaces in a murine model of high-dose bisphosphonates (BPs). MATERIALS AND METHODS: Sixty-four rats were randomly allocated into four groups: control group with HFB implants (CG-HFB), control group with HFL implants (CG-HFL), BP group with HFB implants (BP-HFB), and BP group with HFL implants (BP-HFL). Animals were euthanized after 15 and 45 days (n=8). The dependent variables assessed were the removal torque (biomechanical analysis), the bone volume around the implants (%BV/TV) (microtomographic analysis), the bone-implant contact (%BIC), the bone between the threads (%BBT) (histomorphometric analysis), and the expression of bone metabolism markers (immunohistochemistry analysis). RESULTS: The CG-HFL and BP-HFL groups presented higher removal torque than the CG-HFB and BP-HFB implants. The %BIC of the CG-HFL surfaces was slightly higher than that of the CG-HFB implants. The BP-HFB and BP-HFL groups presented a higher %BIC than that of the CG-HFB and CG-HFL groups (p<0.001). BP therapy also increased the %BBT at both implant surfaces. Higher levels of ALP were observed in the matrix region of bone tissue on the HFL surfaces than on the HFB surfaces. CONCLUSION: Both surfaces enable osseointegration in rats under BP therapy. CLINICAL RELEVANCE: The study demonstrates that hydrophobic (HFB) and hydrophilic (HFL) implant surfaces can promote osseointegration in rats undergoing bisphosphonate therapy. The HFL surfaces exhibited improved biomechanical performance, higher bone-implant contact, and increased bone volume, suggesting their potential clinical relevance for implant success in individuals on bisphosphonate treatment.

Strontium ranelate improves post-extraction socket healing in rats submitted to the administration of bisphosphonates.

The aim of this study was to evaluate the effect of strontium ranelate (Sr) on post-extraction socket healing in rats submitted to the administration of bisphosphonates. Sixty rats were submitted to the tooth extraction of the first lower molar after 60 days of the daily administration of saline solution (SS) or alendronate (ALN). Then, the animals were allocated into six groups namely CTR: administration of SS during the whole experiment, ALN: administration of ALN during the whole experiment, ALN/SS: application of SS for 30 days after extraction in animals previously treated with ALN, ALN/Sr: application of Sr for 30 days after extraction in animals previously treated with ALN, ALN/S60: ALN therapy interruption 30 days before the extraction followed by the application of SS for 60 days, and ALN/Sr60: ALN therapy interruption 30 days before the tooth extraction followed by the application of Sr for 60 days. The healing of the post-extraction sockets was evaluated by microCT and histomorphometry. The use of ALN induced partial bone necrosis, inflammatory infiltration, and a delay in soft tissue healing; the use of Sr improved the connective tissue organization. Sr has subtle positive effects on the post-extraction healing in animals submitted to the administration of bisphosphonate.

Alendronate Impairs Healing of Calvaria Critical Defects After Bone Graft With Different Bone Substitute Materials.

PURPOSE: The aim of this preclinical study was to evaluate the healing of critical-sized defects (CSDs) in the calvarial bone of rats grafted with deproteinized bovine bone graft (DBB) and with a combination of hydroxyapatite (HA) and ß-tricalcium phosphate (TCP) and bisphosphonate treatment. MATERIALS AND METHODS: Eighty-four animals were randomly divided into 2 groups according to the type of solution administered: the control group (CTR, saline solution) and the test group (alendronate [ALD]; sodium alendronate-50 µg/kg/day). Medications were administered via oral gavage starting 15 days before the surgical procedure until the end of the experiment. A CSD (5 mm in diameter) was made in the calvaria of each animal, and the rats were randomly allocated to 3 subgroups according to the biomaterial used to fill the defect: coagulum, DBB, and HA/TCP. The animals were sacrificed 15 and 60 days after the surgical procedure (n = 7 animals/period/subgroup). Microcomputed tomography was used to evaluate the percentage of mineralized tissues (volume). The amount of newly formed bone and remaining bone substitute material in the calvaria were analyzed by histomorphometry. RESULTS: There were no differences between the CTR and ALD groups with regard to the volume of mineralized tissues. The DBB and HA/TCP subgroups of CTR animals presented a significant increase in newly formed bone compared with these subgroups of ALD animals after 60 days of healing. CONCLUSIONS: Collectively, our findings indicate that the use of oral ALD reduced bone formation in CSD in the calvaria of rats grafted with DBB and HA/TCP.

Low-level laser therapy (LLLT) in sites grafted with osteoconductive bone substitutes improves osseointegration.

The aim of this study was to evaluate the osseointegration of implants placed in areas grafted with different osteoconductive bone substitutes irradiated with infrared low-level laser therapy (LLLT). Fifty-six rats were randomly allocated into 4 groups: DBB, bone defects filled with deproteinized bovine bone graft (DBB); HA/TCP, bone defects filled with biphasic ceramic made of hydroxyapatite and ß-tricalcium phosphate (HA/TCP); DBB-L, bone defects filled with DBB and treated by LLLT; HA/TCP-L, bone defects filled with HA/TCP and treated by LLLT. Bone defects were performed in the tibia of each animal and filled with the different biomaterials. The grafted areas were treated with LLLT (λ 808 nm, 100 mW, ϕ ∼ 0.60 mm) in 7 sessions with 48 h between the irradiations. After the 60-day period, the implants were placed, and the animals were euthanized after 15 and 45 days. The osseointegration and bone repair in the grafted area were evaluated by biomechanical, microtomographic and histometric analyses, and the expression of some bone biomarkers was evaluated by immunohistochemistry analysis. LLLT induced higher degree of osseointegration, which was associated with the greater expression of BMP2 and OCN. LLLT performed in areas grafted with osteoconductive bone substitutes prior to implant placement improves osseointegration.

Loading deproteinized bovine bone with strontium enhances bone regeneration in rat calvarial critical size defects.

OBJECTIVE: To evaluate the effect of grafting with strontium (Sr)-loaded deproteinized bovine bone (DBB) on bone healing in calvarial critical size defects (CSD) in rats. MATERIAL AND METHODS: Two circular bone defects (5 mm in diameter) were created in the calvaria of 42 rats. One of the defects, randomly chosen, was grafted with (a) DBB, (b) DBB loaded with 19.6 µg/g of Sr (DBB/Sr1), or (c) DBB loaded with 98.1 µg/g of Sr (DBB/Sr2). The other defect was left empty as negative control. Groups of seven animals from each of the groups were euthanized 15 and 60 days post-op. Bone healing in the CSD was evaluated by micro-CT and histology/histomorphometry and immunohistochemistry. RESULTS: DBB/Sr2-grafted sites showed statistically significantly shorter radiographic residual defect length compared with DBB/Sr1- and DBB-grafted sites, and with empty controls at 60 days. Further, the amount of new bone formation in the DBB/Sr1- and DBB/Sr2-grafted sites was significantly higher compared with that in the DBB-grafted sites at 60 days. A larger number of DBB/Sr1- and DBB/Sr2-grafted sites presented with no- or only limited to mild inflammation, compared with the DBB-grafted sites, especially at 60 days. Higher expression of osteocalcin was observed in DBB/Sr1- and DBB/Sr2-grafted sites as compared to DBB-grafted sites. CONCLUSION: Grafting with Sr-loaded DBB enhanced bone formation in CSD in rats, when compared with grafting with non-loaded DBB. CLINICAL RELEVANCE: Grafting with Sr-loaded DBB may enhance bone formation in bone defects.

Use of a Non-Crosslinked Collagen Membrane During Guided Bone Regeneration Does Not Interfere With the Bone Regenerative Capacity of the Periosteum.

PURPOSE: To assess whether the use of a non-crosslinked porcine collagen type I and III bi-layered membrane inter-positioned between the periosteum and a bone defect would interfere with the bone regenerative capacity of the periosteum. MATERIALS AND METHODS: Sixty rats, each with 1 critical-size calvarial defect (CSD; diameter, 5 mm) in the parietal bone, were randomly allocated to 1 of 3 equal-size groups after CSD creation: 1) the periosteum was excised and the flap was repositioned without interposition of a membrane (no-periosteum [NP] group); 2) the flap including the periosteum was repositioned (periosteum [P] group); and 3) a non-crosslinked collagen membrane was inter-positioned between the flap, including the periosteum, and the bone defect (membrane [M] group). Micro-computed tomography, qualitative histology, immunohistochemistry, and reverse transcription real-time quantitative polymerase chain reaction were performed at 3, 7, 15, and 30 days postoperatively. RESULTS: A markedly increased radiographic residual defect length was observed in the NP group compared with the P group at 30 days. The NP group also presented a smaller radiographic bone fill area than the P group at 15 and 30 days and then the M group at 30 days. The P and M groups exhibited considerably greater expression of bone morphogenetic protein-2 and osteocalcin than the NP group at 7 days; expression of transforming growth factor-ß1 was considerably greater in the NP group at 15 days. Further, the P group presented considerably higher gene expression levels of Runx2 and Jagged1 at 7 days and of alkaline phosphatase at 3 and 15 days compared with the M and NP groups. CONCLUSION: Interposition of this specific non-crosslinked collagen membrane between the periosteum and the bone defect during guided bone regeneration interferes only slightly, if at all, with the bone regenerative capacity of the periosteum.

Treatment of periodontal disease with an Er,Cr:YSGG laser in rats exposed to cigarette smoke inhalation.

The purpose of this study was to evaluate the erbium, chromium:yttrium-scandiumgallium-garnet (Er,Cr:YSGG) laser irradiation in the treatment of periodontitis in rats exposed to cigarette smoke inhalation (CSI). Ligatures were placed in the maxillary second molars. After a 15-day period, the ligatures were removed and 180 animals were randomly divided into six groups: (1) CSRP group--CSI and manual scaling and root planing (SRP) treatment; (2) CL group--CSI and Er,Cr:YSGG laser irradiation; (3) CSRP + L group-CSI, SRP, and Er,Cr:YSGG irradiation; (4) SRP group-manual SRP; (5) L group--Er,Cr:YSGG irradiation; (6) SRP + L group--SRP and Er,Cr:YSGG irradiation. At 7, 15, and 30 days after treatments, animals were euthanized and histologic, histometric, immunohistochemistry, and real-time PCR analyses were performed. Histometrically, no differences were observed in the SRP, L, and SRP + L groups exposed to CSI. The CSRP group showed more bone formation at 30 days than at 15 days (p < 0.01) but less bone at 30 days than the CL group at 30 days (p < 0.05). Immunohistochemical staining was positive for osteoblasts, fibroblasts, and osteoclasts. Real-time PCR showed more (vascular endothelial growth factor) VEGF expression in the L (p < 0.05) and SRP + L (p < 0.01) groups at 30 days than at 15 days and less VEGF expression in the CSRP group at 30 days than at 15 days (p < 0.05). There was no difference in fibroblast growth factor (FGF) expression. The Er,Cr:YSGG laser irradiation promotes favorable conditions for tissue repair even in animals exposed to CSI, with similar results as those achieved from manual scaling and root planing.

Effect of Er,Cr:YSGG laser application in the treatment of experimental periodontitis.

The purpose of this study was to evaluate the influence of an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in the absence or presence of manual scaling and root planning (SRP) for the treatment of induced periodontitis in rats. Ligatures were placed in the subgingival region of the maxillary first molar. After a 7-day period, the ligatures were removed, and 40 rats were randomly divided into four groups (G), as follows: (GI) no treatment, (GII) scaling and root planning (SRP) with curettes, (GIII) Er,Cr:YSGG laser irradiation and (GIV) SRP with curettes followed by Er,Cr:YSGG laser irradiation. Seven and 30 days after the treatment, the animals were sacrificed and histologic, histometric and immunohistochemistry analyses were performed. All groups showed similar histopathological characteristics during the evaluation period. The histometric analysis was confirmed using Bonferroni and paired t tests. At 7 and 30 days, groups II, III and IV exhibited greater bone formation in the furcation area when compared to group I (p < 0.0001; p < 0.05). During the 7-day period, the groups irradiated with the laser (III and IV) showed a statistically larger new bone area than the group treated with SRP (II) (p < 0.01). Immunohistochemistry analysis revealed that the control group exhibited a higher expression of tartrate-resistant acid phosphatase (TRAP) and the receptor activator of nuclear factor κΒ ligand (RANKL) when compared to groups II, III and IV (p < 0.05). All treatments were able to reduce the inflammatory processes, consequently enabling the repair of periodontal tissues. The results achieved with the application of the Er,Cr:YSGG laser suggest that this laser can stimulate greater bone formation, especially over a shorter period of time.

Dynamics of bone healing after osteotomy with piezosurgery or conventional drilling - histomorphometrical, immunohistochemical, and molecular analysis.

BACKGROUND: Piezosurgery is an osteotomy system used in medical and dental surgery. Many studies have proven clinical advantages of piezosurgery in terms of quality of cut, maneuverability, ease of use, and safety. However, few investigations have tested its superiority over the traditional osteotomy systems in terms of dynamics of bone healing. Therefore, the aim of this study was to evaluate the dynamics of bone healing after osteotomies with piezosurgery and to compare them with those associated to traditional bone drilling. METHODS: One hundred and ten rats were divided into two groups with 55 animals each. The animals were anesthetized and the tibiae were surgically exposed to create defects 2 mm in diameter by using piezosurgery (Piezo group) and conventional drilling (Drill group). Animals were sacrificed at 3, 7, 14, 30 and 60 days post-surgery. Bone samples were collected and processed for histological, histomorphometrical, immunohistochemical, and molecular analysis. The histological analysis was performed at all time points (n = 8) whereas the histomorphometrical analysis was performed at 7, 14, 30 and 60 days post-surgery (n = 8). The immunolabeling was performed to detect Vascular Endothelial Growth Factor (VEGF), Caspase-3 (CAS-3), Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), and Osteocalcin (OC) at 3, 7, and 14 days (n = 3). For the molecular analysis, animals were sacrificed at 3, 7 and 14 days, total RNA was collected, and quantification of the expression of 21 genes related to BMP signaling, Wnt signaling, inflammation, osteogenenic and apoptotic pathways was performed by qRT-PCR (n = 5). RESULTS: Histologically and histomorphometrically, bone healing was similar in both groups with the exception of a slightly higher amount of newly formed bone observed at 30 days after piezosurgery (p < 0.05). Immunohistochemical and qRT-PCR analyses didn't detect significant differences in expression of all the proteins and most of the genes tested. CONCLUSIONS: Based on the results of our study we conclude that in a rat tibial bone defect model the bone healing dynamics after piezosurgery are comparable to those observed with conventional drilling.

Influence of obesity on osseointegration of implants with different surface treatments: A preclinical study.

OBJECTIVE: The aim of the present study was to evaluate the effect of obesity on the osseointegration of implants with hydrophobic and hydrophilic surfaces. MATERIALS AND METHODS: Sixty-four male rats were distributed among four experimental groups: H-HB (Healthy/Hydrophobic): healthy animals with hydrophobic implants; H-HL (Healthy/Hydrophilic): healthy animals with hydrophilic implants; O-HB (Obese/Hydrophobic): animals with induced obesity and hydrophobic implants; O-HL (Obese/Hydrophilic): animals with induced obesity and hydrophilic implants. One hundred and twenty-eight implants were installed in the tibiae of the animals bilaterally (64 on the left tibiae and 64 on the right one) after 75 days of a specific diet (standard or high-fat diet) and euthanasia was performed in the experimental periods of 15 and 45 days after implant placement. Bone formation was assessed by biomechanical analysis (on the left tibiae of each animal), and microtomographic and histomorphometric analyses (on the right tibiae of each animal). Statistical analysis was performed using the Shapiro-Wilk test for normality and ANOVA followed by Tukey test to observe whether there was a significant difference between groups (p < 0.05); the t-test was used to compare the animals' body weight. RESULTS: The biomechanical analysis showed an increase in the removal torque value of animals after 45 days in comparison to after 15 days, with the exception of O-HB groups. The microtomographic analysis demonstrated no significant differences in the mineralized bone tissue volume between the groups. In the histomorphometric analysis, the H-HL/45 day group/period demonstrated higher bone-implant contact, in comparison to H-HL/15 days and the O-HL/45 day group/period showed an increase in bone area between the implant threads, in comparison to O-HL/15 days. CONCLUSION: In conclusion, obesity does not interfere with the osseointegration of hydrophobic and hydrophilic implants.

Osseointegration of implants with superhydrophilic surfaces in rats with high serum levels of nicotine.

This study aimed to evaluate the effect of nicotine administration on the osseointegration of a superhydrophilic implants surface on rat tibiae. Thirty-two rats were used and divided into 2 groups according to the administration or not of nicotine: HH - Installation of implants with superhydrophilic surfaces in healthy animals; and HN - Installation of implants with superhydrophilic surfaces in animals subjected to nicotine administration. The animals were euthanized 15 and 45 days after implant placement (n = 8). Osseointegration was assessed by means of biomechanical analyses (removal torque), microcomputed tomography (volume of bone around the implants- %BV/TV), and histomorphometry (bone-implant contact -%BIC and the bone area between implant threads -%BBT). The animals subject to the nicotine administration presented lower removal torque than the control animals at the 45-day period (21.88 ± 2.80 Ncm vs. 17.88 ± 2.10 Ncm). The implants placed in the control rats presented higher %BIC (54.26 ± 6.59% vs. 39.25 ± 4.46%) and %BBT (50.57 ± 5.28% vs. 32.25 ± 5.24%) than the implants placed in nicotine animals at 15-day period. The nicotine administration reduces the osseointegration at 15 days, however, the superhydrophilic surface equalized the osseointegration in nicotine-exposed animals compared with healthy animals after 45 days of implant placement.

Effects of red and infrared laser on post extraction socket repair in rats subjected to alendronate therapy.

This study evaluated the effect of photobiomodulation therapy (PBMT) with a red or infrared laser on the repair of post extraction sockets in rats administered alendronate (ALN). Forty male rats were randomly allocated into four groups: Control Group (CTR): subcutaneous administration of saline solution throughout the experimental period; Alendronate Group (ALN): subcutaneous administration of alendronate during the entire experimental period; Alendronate/Red Laser Group (ALN/RL): administration of ALN and irradiation with a GaAlAs laser (λ 660 nm); and Alendronate/Infrared Laser Group (ALN/IRL): administration of ALN and irradiation with a GaAlAs laser (λ 830 nm). The first lower molars were extracted 60 days after the beginning of the administration of the drugs. The PBMT was applied after tooth extraction (7 sessions with intervals of 48 hours between sessions). Thirty days after tooth extraction, the animals were euthanized. Micro-CT and histometric analysis were performed to assess the bone healing and soft tissue repair of the tooth socket. The ALN group presented with more bone than the CTR; however, most of this bone was necrotic. ALN does not affect the bone microarchitecture. On the other hand, PBMT with IRL enhances the bone density due to the increase in the number and reduction in the spacing of the trabeculae. The amount of vital bone and connective tissue matrix was higher in the ALN/RL and ALN/IRL groups than in the ALN and CTR groups. PBMT enhanced the healing of the post extraction sockets in rats subjected to ALN administration. Furthermore, IRL improved the new bone microarchitecture.

Chlorin-based photosensitizer under blue or red-light irradiation against multi-species biofilms related to periodontitis.

In our previous study, Chlorin-e6 (Ce6) demonstrated a significant reduction of microorganisms' viability against single-species biofilm related to periodontitis once irradiated by red light (660 nm). Also, higher bacteria elimination was observed under blue light (450 nm) irradiation. However, the use of blue light irradiation of Ce6 for antimicrobial administration is poorly explored. This study evaluated the effect of chlorin-e6-mediated antimicrobial photodynamic therapy (aPDT) using different wavelengths (450 or 660 nm) against multi-species biofilms related to periodontitis. Streptococcus oralis, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans composed the mature biofilm developed under proper conditions for five days. aPDT was performed using different concentrations of Ce6 (100 and 200 µM), wavelengths (450 or 660 nm), and comparisons were made after qPCR assay and confocal laser scanning microscopy (CLSM) analysis. The greatest bacterial elimination was observed in the groups where Ce6 was used with blue light, for S. orallis (2.05 Log10 GeQ mL-1, p < 0.0001) and P. gingivalis (1.4 Log10 GeQ mL-1, p < 0.0001), aPDT with red light showed significant bacteria reduction only for S. orallis. aPDT with blue light demonstrated statistically higher elimination in comparison with aPDT with red light. The aPDT did not show a statistically significant effect when tested against A. actinomycetemcomitans and F. nucleatum (p=0.776 and 0.988, respectively). The aPDT using blue light showed a promising higher photobiological effect, encouraging researchers to consider it in the irradiation of Ce6 for further investigations.

Effects of the Er,Cr:YSGG laser on bone and soft tissue in a rat model.

The purpose of this study was to investigate the histological changes that occur in rat soft and hard tissues after Er,Cr:YSGG laser surgery. Each of 20 rats was submitted to four procedures which were randomly distributed to the right and left sides of the animal: procedure 1 dorsal incision with a scalpel; procedure 2 dorsal incision with a 2.0-W Er,Cr:YSGG laser; procedure 3 skull defect created with a diamond bur; procedure 4 skull defect created with a 3.0-W Er,Cr:YSGG laser. The animals were killed 3, 7, 15 and 30 days after surgery, and histological examinations were performed. The histometric analysis of the bone defects was evaluated using an unpaired t-test. Initially, the dorsum showed more histological signs of repair following procedure 1, although similar healing responses following procedures 1 and 2 were seen on day 30 after surgery. By day 30 the bone formation observed following procedure 4 was much more evident than following procedure 3. The unpaired t-test identified significant differences in bone formation on day 30 (p = 0.01), whereas a greater bone percentage was seen following procedure 4 than following procedure 3 (79.96 ± 10.30% and 58.23 ± 9.99%, respectively). Thus, histological repair of the Er,Cr:YSGG laser wounds was similar to that of the scalpel wounds. However, skull defects created with the Er,Cr:YSGG laser showed greater bone formation than defects created with the bur. Within the limitations of this study, we can conclude that the Er,Cr:YSGG laser is a promising surgical instrument in vivo, particularly for bone surgery.

Comparison of the osseointegration of implants placed in areas grafted with HA/TCP and native bone.

This study evaluated the osseointegration of implants in areas grafted with biphasic ceramic based on hydroxyapatite/ß-tricalcium phosphate (HA/TCP) and in native bone (NB). Twenty-eight rats were randomly assigned into two groups of 14 animals each: HA/TCP group: implants installed in areas grafted with HA/TCP and NB group: implants installed in areas of native bone. Bone defects were made in both tibiae of the rats belonging to the HA/TCP group and then filled with this bone substitute. After 60 days, the rats were submitted to surgical procedures for implant placement in grafted areas in both tibiae in the HA/TCP group while the implants were installed directly in native bone in the NB group. The animals were euthanized 15 and 45 days, respectively, after the implant placement. Biomechanical (removal torque), microtomographic (volume of mineralized tissues around the implants), and histomorphometric (Bone-Implant contact-%BIC and bone area between the implant threads-%BBT) analyzes were conducted to assess the osseointegration process. The HA/TCP group showed lower values of removal torque, volume of mineralized tissue around the implants, lower %BIC, and %BBT compared to the NB group in both experimental periods. Osseointegration of implants placed in grafted areas with HA/TCP was lower compared to the osseointegration observed in native bone areas. RESEARCH HIGHLIGHTS: The areas grated with HA/TCP presented poor biological conditions. The reduced biological properties for bone formation impaired the osseointegration in HA/TCP grafted areas.

Comparison of osseointegration in areas grafted with different osteoconductive biomaterials. Preclinical study.

This study evaluated osseointegration in areas grafted with deproteinized bovine bone (DBB) and biphasic ceramic based on hydroxyapatite and beta-tricalcium phosphate (HA/TCP) in rat tibias. Noncritical bone defects were made in the tibias of 28 rats that were randomly assigned to 2 groups: DBB: DBB-filled defects and HA/TCP: HA/TCP-filled defects. Bone defects were made in the tibias bilaterally and filled with biomaterials. After 60 days, the implants were inserted, and the animals were euthanized 15 and 45 days after the implants were installed. Osseointegration was evaluated by biomechanical, microtomographic and histometric analysis. Implants installed in the defects filled with DBB presented higher removal torque forces (2.33 ± 0.51 Ncm vs. 1.50 ± 0.54 Ncm) and mineralized tissue volume around implants at 15 days (34.96 ± 3.68 % vs. 25.61 ± 2.95 %) and greater bone-implant contact (20.87 ± 8.28 % vs. 11.52 ± 7.42 %) and bone area within implant threads (26.83 ± 12.35 % vs. 11.98 ± 7.56 %) at 45 days compared to the measurements of implants in areas grafted with HA/TCP. Implants installed in defects in areas grafted with DBB had a better osseointegration pattern than implants placed in defects in areas grafted with HA/TCP.

Implants with hydrophilic surfaces equalize the osseointegration of implants in normo- and hyperglycaemic rats.

The purpose of this study was to evaluate the effect of a surface modified by blasting and acid attack and maintained in an isotonic solution compared to a machined surface on osseointegration in normo- and hyperglycaemic animals. Sixty-four animals were allocated into 4 groups with 16 animals each, and they were subdivided into two experimental periods (15 and 45 days), with 8 animals in each group. The groups were divided according to the type of implant that was installed in the animals' tibia and the animals' systemic condition: CM - Machined implants placed in Healthy animals; CH - Hydrophilic implants placed in Healthy animals, HM - Machined implants placed in animals with hyperglycaemia; HH- Hydrophilic implants installed in animals with hyperglycaemia. The following analyses were performed: biomechanical (removal torque), microtomographic (evaluation of the bone volume around the implants- BV/TV), and histomorphometric (evaluation of bone-implant contact BIC% and of the bone formation area between the threads BBT%). It was found that the implants with hydrophilic surfaces presented higher removal torques and quantities of BV/TV% and higher BIC% and BBT% values in normo- and hyperglycaemic animals. The results of this study indicated that the hydrophilic surface accelerates the osseointegration process (~ 15% BIC/BBT at 15-day period), especially in animals with hyperglycaemia. The hydrophilic surface equaled the osseointegration between normo- and hyperglycaemic animals, reversing the negative potential of hyperglycaemia on the osseointegration process.

Dexamethasone-Loaded Ureasil Hydrophobic Membrane for Bone Guided Regeneration.

Physical barrier membranes have been used to release active substances to treat critical bone defects; however, hydrophilic membranes do not present a prolonged release capacity. In this sense, hydrophobic membranes have been tested. Thus, this study aimed to develop hydrophobic membranes based on mixtures of ureasil-polyether-type materials containing incorporated dexamethasone (DMA) for the application in guided bone regeneration. The physicochemical characterization and biological assays were carried out using small-angle X-ray scattering (SAXS), an in vitro DMA release study, atomic force microscopy (AFM), a hemolysis test, and in vivo bone formation. The swelling degree, SAXS, and release results revealed that the u-PPO400/2000 membrane in the proportion of 70:30 showed swelling (4.69% ± 0.22) similar to the proportions 90:10 and 80:20, and lower than the proportion 60:40 (6.38% ± 0.49); however, an equal release percentage after 134 h was observed between the proportions 70:30 and 60:40. All u-PPO materials presented hemocompatibility (hemolysis ≤2.8%). AFM results showed that the treatments with or without DMA did not present significant differences, revealing a flat/smooth surface, with no pores and/or crystalline precipitates. Finally, in vivo results revealed that for both the commercial hydrophilic membrane and u-PPO400/2000 (70:30) after 60 days, the bone formation volume was 21%. In conclusion, hybrid membranes present unique characteristics for treating critical bone defects, considering the delayed and prolonged release results associated with the physical barrier capacity.

Effects of low-level laser therapy (685 nm) at different doses in osteogenic cell cultures.

The present in vitro study evaluated parameters of osteogenesis under the influence of low-level laser therapy (LLLT) at different doses. Osteogenic cells originated from rat calvaria were cultivated in polystyrene plates and exposed to a laser irradiation using an indium-gallium-aluminum phosphide therapeutic laser (InGaAIP), at wavelength of 685 nm, power of 35 mW, 600-µm-diameter optical fiber, and continuous wave. In the attempt of observing the existence of a dose response and its effects, laser irradiation was performed at 25, 77, and 130 J/cm(2) (7, 22, and 37 s, respectively). The following parameters were assessed: growth curve (4, 7, and 11 days), cell viability (24 h), and nodular formation of mineralized matrix (14 days). The results did not show significant differences related to the growth curve (4, 7, and 11 days) and cell viability (24 h). Within 14 days, osteogenic cultures showed nodular areas with well-defined calcified matrix. The total area stained with Alizarin Red did not show any differences between doses of 25 and 130 J/cm(2). However, the percentage of stained area was significantly higher in the 25 J/cm(2) group when compared to the group of 77 J/cm(2) (Kruskal-Wallis test, p < 0.05). It was possible to conclude that the 685-nm laser irradiation (at 25, 77, and 130 J/cm(2)) did not influence cell growth and proliferation, although the extracellular mineralization process may have its pattern altered by the LLLT on osteogenic cell cultures.

LASER in periodontal treatment: is it an effective treatment or science fiction?

There are several studies that evaluate the use of lasers in periodontal treatment in non-surgical or surgical therapy. However, while several studies showed clinically beneficial effects of some lasers in periodontal treatment, there are few clinical reports of additional advantages of lasers as adjunctive treatments in periodontology. The aim of this paper is to demonstrate and critically analyze the level of scientific evidence of effects of low-level lasers and high-power lasers in periodontology. A narrative review of the studies was carried out in each topic and type of laser or periodontal treatment. In nonsurgical periodontal therapy the results showed that there is an additional clinical benefit when using a diode laser (DL) associated with scaling and root planing (SRP) in patients with moderate to severe periodontitis. The Er:YAG laser seems to be the most suitable for nonsurgical periodontal therapy and promotes the same clinical effects as conventional therapy. In periodontal surgery vaporization of the gingival or mucosal tissue can be carried out with DL, CO2, Nd:YAG, Er:YAG and Er,Cr:YSGG lasers. Photobiomodulation (PBM), mediated by low-level lasers associated with non-surgical periodontal therapy, promotes additional benefits in the short term and accelerates the bone and gingival tissue repair process and also reduces postoperative symptoms of periodontal surgery. The effect of antimicrobial Photodynamic Therapy is relevant in the initial reevaluation periods. Studies have shown controversial results of the use of lasers in periodontics, and this fact may be due to the lack of standard parameters of irradiation in each clinical application.