Acute-phase response following full-mouth versus quadrant non-surgical periodontal treatment: A randomized clinical trial.

AIM: A moderate acute-phase response occurs 24-h following full-mouth non-surgical treatment (FM-SRP). The aim of this study was to compare acute-phase (24-h) and medium-term (3 months) inflammation after quadrant scaling (Q-SRP) versus FM-SRP. MATERIAL & METHODS: Thirty-eight periodontitis-affected subjects were randomly allocated to FM-SRP or Q-SRP after a baseline visit. Periodontal and anthropometric parameters were collected at baseline and 3 months. Serum samples were drawn at baseline, 1, 7, and 90 days after treatment. High-sensitivity assays of inflammation and endothelial assays were performed. RESULTS: FM-SRP produced a greater acute-phase response after 24 h [threefold increase in C-reactive protein (CRP), twofold increase in interleukin (IL-6), and a slight increase in tumour necrosis factor]. No differences in systemic biomarkers were noted between groups at any later follow-ups. Both periodontal treatments produced a comparable improvement in clinical periodontal parameters with no between-group differences. Treatment time was positively associated with the relative 24-h increase in CRP (R = 0.5, p < 0.001) and IL-6 (R = 0.5, p = 0.002), while the number of deeper (>6 mm) pockets predicted only the relative increase in IL-6 (R = 0.4, p < 0.05). CONCLUSIONS: FM-SRP triggers a moderate acute-phase response of 24 h duration compared to Q-SRP. Further research is needed to assess the eventual impact of such findings on the risk of vascular events is advocated. (ClinicalTrials.gov NCT01857804).

Protein adsorption on a laser-modified titanium implant surface.

PURPOSE: The aim of this study was to investigate the earlier phase of the osseointegration of a laser-treated implant surface in terms of human protein adsorption. MATERIALS AND METHODS: Titanium surfaces were divided into machined (M), sandblasted (SB), and laser-treated (LT). The LT surfaces were created with an Nd diode-pumped laser in Q-switching, whereas the SB were treated with Al2O3. An x-ray photoelectron spectroscopy (XPS) analysis of titanium surface was performed. Titanium discs were used for albumin and fibronectin adsorption evaluation through fluorescence intensity. Fibronectin evaluation was also made with Western Blot analysis on experimental implants. RESULTS: LT discs appeared to trigger a higher albumin and fibronectin adsorption with a regular pattern. The mean count of albumin adsorption was 0.29 and 3.8 for SB and LT, respectively (P = 0.016), whereas fibronectin values were 0.67 and 4.9 for (SB) and (LT) titanium (P = 0.02). XPS analysis showed that titanium, oxygen, carbon, and nitrogen were found on all 3 surfaces. CONCLUSION: Laser-engineered porous titanium surface seems to promote, in vitro, the adsorption of albumin and fibronectin more than sandblasted (SB) or machined (M) implants.

Dental plaque, gingival inflammation and tooth -discolouration with different commercial -formulations of 0.2% chlorhexidine rinse: a double-blind randomised controlled clinical trial.

PURPOSE: To investigate the efficacy of various formulations of chlorhexidine 0.2% (CHX) in terms of plaque and gingival bleeding control compared to each other and to saline rinse (CTRL) over a 35-day rinsing period. MATERIALS AND METHODS: Seventy subjects were randomly allocated to one of 4 groups rinsing twice daily for 35 days. The different groups used CHX 0.2% rinse with alcohol (CHX1) and without alcohol (CHX2), with an antidiscolouration system (CHX3) or saline rinse (CTRL). Clinical examinations to evaluate full-mouth plaque scores (FMPS) and periodontal parameters were performed at baseline, 7, 21 and 35 days. Tooth discolouration (TD) was measured at each time point using digital photographs and spectrophotometric analysis. RESULTS: At 35 days, CTRL showed the highest levels of plaque. The mean changes in FMPS from baseline were 69.8% ± 6.8 for CHX1, 57.5% ± 9.8 for CHX2, 43.7% ± 9.8 for CHX3 and 25.8% ± 7.7 for CTRL. Statistically significant differences were demonstrated between CHX1 and CHX3 (p = 0.02), CHX2 vs CHX3 (p ≤ 0.05) and CHX1/CHX2 vs CHX3 (p < 0.05). In contrast, CHX3 appeared more effective in reducing inflammatory indexes. TD increased over time in 60% to 70% of participants, although lighter staining was found in the CHX3 group. Greater FMPS reduction was observed in participants with staining vs without staining (26.0% ± 12.3, p = 0.04). CONCLUSION: Conventional CHX appeared more effective in terms of plaque reduction. Interestingly, the newest formulation showed a higher control of gingival inflammation. Staining was associated with lower plaque levels.

Plasticity of human dental pulp stromal cells with bioengineering platforms: a versatile tool for regenerative medicine.

In recent years, human dental pulp stromal cells (DPSCs) have received growing attention due to their characteristics in common with other mesenchymal stem cells, in addition to the ease with which they can be harvested. In this study, we demonstrated that the isolation of DPSCs from third molar teeth of healthy individuals allowed the recovery of dental mesenchymal stem cells that showed self-renewal and multipotent differentiation capability. DPSCs resulted positive for CD73, CD90, CD105, STRO-1, negative for CD34, CD45, CD14 and were able to differentiate into osteogenic and chondrogenic cells. We also assayed the angiogenic potential of DPSCs, their capillary tube-like formation was assessed using an in vitro angiogenesis assay and the uptake of acetylated low-density lipoprotein was measured as a marker of endothelial function. Based on these results, DPSCs were capable of differentiating into cells with phenotypic and functional features of endothelial cells. Furthermore, this study investigated the growth and differentiation of human DPSCs under a variety of bioengineering platforms, such as low frequency ultrasounds, tissue engineering and nanomaterials. DPSCs showed an enhanced chondrogenic differentiation under ultrasound application. Moreover, DPSCs were tested on different scaffolds, poly(vinyl alcohol)/gelatin (PVA/G) sponges and human plasma clots. We showed that both PVA/G and human plasma clot are suitable scaffolds for adhesion, growth and differentiation of DPSCs toward osteoblastic lineages. Finally, we evaluated the interactions of DPSCs with a novel class of nanomaterials, namely boron nitride nanotubes (BNNTs). From our investigation, DPSCs have appeared as a highly versatile cellular tool to be employed in regenerative medicine.

Does enamel matrix derivative application provide additional clinical benefits in residual periodontal pockets associated with suprabony defects? A systematic review and meta-analysis of randomized clinical trials.

OBJECTIVE: To review the effectiveness of enamel matrix derivative (EMD) in the treatment of periodontal pockets of suprabony defects. METHODS: Randomized Clinical Trials comparing open flap debridement (OFD) versus EMD in periodontal suprabony defects were identified through electronic and manual search. Screening, data extraction and quality assessment were conducted. The primary outcome measures were tooth survival (TS) and clinical attachment level (CAL) gain. Pocket probing depth (PPD) reduction and recession (REC) increase were secondary outcome measures. Information concerning clinical and radiological bone gain was also collected. RESULTS: The search identified 1170 studies, three articles reporting on (99 subjects/358 teeth) met the inclusion criteria and were included. No tooth was lost during follow-up (8-12 months). The adjunctive mean benefit of EMD was: 1.2 mm for CAL gain [confidence interval (CI): (0.9, 1.4), p < 0.00001, I(2) = 66%], 1.2 mm for the PPD reduction (CI: [0.8, 1.5], p < 0.0001, I(2) = 0%), -0.5 mm for the REC increase (CI: [-0.8, -0.2], p = 0.003, I(2) = 0%). Potential risk of bias was identified. CONCLUSIONS: No differences were noted in TS but EMD application resulted in clinical and radiographic additional benefits compared to OFD alone. Nevertheless, the paucity of data, the risk of methodological and potential publication bias suggests caution in interpreting these results while supporting multicenter studies for this specific application.

An aromatase polymorphism (g.132810C>T) predicts risk of bisphosphonate-related osteonecrosis of the jaw.

BACKGROUND: Bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) is an unpredictable, debilitating adverse effect. Recently, genetic polymorphisms have arisen as promising tools to identify patients with a higher risk of drug-related adverse events. AIM: We aimed to examine the association between the aromatase polymorphism g.132810C>T, and the estrogen receptor polymorphisms g.156705T>C and g.156751A>G, and the risk of BP-related ONJ. METHODS: Eighty-three subjects were included in the study. A clinical and radiological examination was conducted on oncologic subjects treated with zoledronic acid. Subjects with histologically confirmed ONJ were included in the test group (n = 30) whereas subjects with good oral health were included in control group (n = 53). Aromatase and estrogen receptor polymorphisms from blood samples were analyzed. RESULTS: The aromatase g.132810C>T polymorphism displayed an over-representation of the TT genotype in the test group (36.67 vs 16.98%; p < 0.05). There was no significant difference in either estrogen receptor polymorphism genotype frequency between the test and control groups. CONCLUSION: Our data suggest a role for the g.132810C>T polymorphism in predicting ONJ risk. These results can pave the way to the personalization of BP therapy, based on individual genotype.

Clinical performance of access flap surgery in the treatment of the intrabony defect. A systematic review and meta-analysis of randomized clinical trials.

AIM: To systematically review the literature and to determine the clinical performance of conservative surgery (CS) for the treatment of intrabony defects (ID). METHODS: RCTs on ID treatment with 12 months of follow-up were identified through electronic databases and hand-searched journals. Primary outcomes were tooth survival, clinical attachment (CAL) gain, probing depth (PD) reduction and gingival recession increase (REC). Weighted means and forest plots were calculated for each outcome variable 12 months after surgery. Long-term stability was explored with RCTs of at least 24 months of follow-up. Subgroup analysis was performed according to the type of flap. RESULTS: Twenty-seven trials reporting 647 subjects and 734 defects were identified. Twelve months after CS, tooth survival was 98% (IQ: 96.77-100), CAL gain 1.65 mm (95% CI: 1.37-1.94; p < 0.0001), PD reduction 2.80 mm (CI: 2.43-3.18; p < 0.0001) and REC increase 1.26 mm (CI: 0.94-1.49; p < 0.0001). Longer follow-up showed similar findings. CI of CAL gain were 1.44-3.52 for recently introduced papilla preservation flaps and 1.25-1.89 mm for access flaps. CONCLUSIONS: The treatment of intrabony defect with CS is associated with high tooth retention and improvement of periodontal clinical parameters. Clinical performance may vary according to the type of surgical flap used.

Effect of laser micromachining of titanium on viability and responsiveness of osteoblast-like cells.

OBJECTIVES: Laser engineering may create hemispherical porosities on titanium surfaces obtaining regular and predetermined rough titanium surfaces. The aim of this study was to assess the viability and the proliferation of primary osteoblast-like cells (OB) to growth factors on titanium surfaces with a different roughness in vitro. MATERIALS AND METHODS: OB were obtained from volunteers undergoing wisdom tooth removal following a standardized protocol. OB were allowed to attach on 4 different titanium surfaces: sandblasted titanium (SBT) disks, 5-, 10-, and 20-µm regular laser-engineered micropore titanium disks. A well with no disk was used as control. Cell morphology was evaluated with scanning electron microscopy. Viability was measured with MTT (3[4,5 dimethylthiazol 2yl]2,5 diphenyltetrazolium bromide) assay. Proliferation rate of attached cells was evaluated with Cell Counting Kit-8 48 hours after platelet-released supernatant (PRS) application. Statistical analysiswas performed with analysis of variance test. RESULTS: All surfaces showed OB attachment on scanning electron microscopy. OB appeared more numerous on 20T surfaces. Laser-engineered surfaces showed higher OB viability than SBT (P < 0.01). In terms of proliferation, viability increase was noted for all groups after platelet-released supernatant application. 20T and SBT disks seemed to trigger the higher cellular proliferation (20T vs 10T, P < 0.05). CONCLUSIONS: Laser-engineered porous titanium surfaces promote viability and proliferation of OB. In particular, hemispherical porosity of 20 µm seems to trigger the higher OB response. Further research is needed to confirm these data.

Systemic inflammation following non-surgical and surgical periodontal therapy.

AIM: To describe the kinetics of serum inflammatory markers after a course of treatment comprising surgical and non-surgical treatment of chronic periodontitis (CP). MATERIAL AND METHODS: Fourteen CP cases received full-mouth non-surgical treatment and, after 6 months, at least two surgical sessions. Blood samples were collected at various time-points after treatment. Blood markers of systemic inflammation/coagulation including leucocyte counts, C-reactive protein (CRP), serum amyloid-A (SAA) and D-dimers and renal function (cystatin C) were determined using high-sensitivity assays. RESULTS: Periodontal treatment resulted in substantial reductions of the number of pockets, gingival bleeding and plaque at 3 and 6 months after non-surgical therapy (p<0.001). Surgical therapy led to an additional reduction of periodontal pockets (p<0.01). Marked increases in the serum levels of CRP and SAA were noted 24 h after non-surgical therapy (p<0.01) and periodontal surgeries (p<0.05). D-dimer levels increased drastically 24 h after non-surgical therapy (p<0.05). The drastic increase of CRP after non-surgical therapy was greater than both the surgical therapy sessions (p<0.05). CONCLUSIONS: Patients undergoing periodontal treatment experience perturbations of systemic inflammation of a greater magnitude after non-surgical than surgical periodontal therapy.

Effects of non-surgical periodontal therapy on the glomerular filtration rate of the kidney: an exploratory trial.

OBJECTIVE: To determine whether non-surgical periodontal treatment (PT) would exert, in subjects with generalized chronic periodontitis (GCP), some beneficial effect on renal function as indicated by surrogate measures of the glomerular filtration rate (GFR). MATERIAL AND METHODS: Twenty GCP systemically healthy subjects were treated with PT. Serum samples were collected at baseline and 1 day, 7, 30, 90 and 180 days after treatment. GFR was evaluated using cystatin C, a serum marker and modification of diet in renal disease (MDRD), an equation involving creatinine, urea and albumin. Serum markers of systemic inflammation such as C-reactive protein (CRP), D-dimer, serum amyloid A (SAA) and fibrinogen were also assessed. RESULTS: The cystatin C level decreased significantly from baseline to the end of the trial (p<0.01). Conversely, MDRD did not vary. A significant inflammatory reaction was produced by PT in the short term. Greater increases were noted for CRP and SAA within 24 h (p<0.001 versus baseline), while D-dimer (p<0.05) and fibrinogen (p<0.01) showed mild variations. The values of inflammatory markers were normalized after 30 days. CONCLUSIONS: GFR, as assessed by cystatin C levels, may be positively affected by PT. Because of the exploratory nature of this trial, further research is needed to investigate this preliminary finding.

Development of an in vitro model on cellular adhesion on granular natural bone mineral under dynamic seeding conditions--a pilot study.

Adhesion of osteogenic cells on biomaterials can be studied with static in vitro models, whereas models representing dynamic seeding conditions are rare. Herein, we present an in vitro model to study cell adhesion on granular biomaterials under dynamic seeding conditions. Radiolabeled osteogenic MC3T3-E1 cells were allowed to adhere to granules of natural bovine bone mineral (NBM) under constant rotation. Adhesion of MC3T3-E1 cells was determined by liquid scintillation counting, and cell morphology was visualized by scanning electron microscopy. Cell viability was determined by MTT assay under static and dynamic conditions, at room and body temperature, and in the presence or absence of serum. We show here that MC3T3-E1 cells rapidly adhere to NBM, reaching a peak 3 h after seeding. Attached cells display characteristic signs of spreading. Five to ten percent of total radioactivity remained on NBM after the removal of nonadherent cells. Viability is maintained at room temperature and under rotation for upto 3 h. This data suggests that the dynamic in vitro model presented here provides a tool to study cell adhesion on granular biomaterials.

Lack of short-term adjunctive effect of systemic neridronate in non-surgical periodontal therapy of advanced generalized chronic periodontitis: an open label-randomized clinical trial.

AIM: To determine if the adjunctive use of intra-muscular neridronate (NE) during non-surgical periodontal treatment (PT) provides, in patients with generalized chronic periodontitis (GCP), adjunctive benefits as compared with PT alone 3 months after the completion of a 3-month NE therapy. MATERIAL AND METHODS: Sixty GCP healthy patients were randomly assigned to control (CG) or test group (TG). CG patients received PT only. Thirty subjects in TG also received adjunctive NE (12.5 mg in an i.m. injection/week for 3 months). Clinical parameters were evaluated at baseline, at the end of NE treatment (3 months after PT) and 3 months after the completion of NE treatment (6 months after the beginning of PT). RESULTS: Groups were balanced at baseline and all clinical parameters showed improvement between baseline and follow-ups. At 6 months improvements from baseline at sites with deep pocket depth (>or=7 mm) were 3.2 mm [95% confidence interval (CI): 2.7-3.9] in CG and 3.0 mm (95% CI: 2.3-3.8) in TG with a non-significant difference of 0.2 mm (95% CI: -1.0-0.5; ANCOVA; p=0.549) between groups. Secondary outcomes did not show significant differences between groups. No major adverse events were reported. CONCLUSIONS: The adjunctive use of NE during PT did not result in additional short-term improvements in periodontal conditions of GCP patients when compared with PT.

The effects of systemic alendronate with or without intraalveolar collagen sponges on postextractive bone resorption: a single masked randomized clinical trial.

Alendronate is a bisphosphonate frequently used to reduce bone resorption. It has been used for osteoporosis, Paget's disease, and also as adjunctive therapy for periodontal disease. The aim of this study was to evaluate the effect of systemic alendronate with or without endoalveolar collagen sponge on vertical bone resorption after lower wisdom tooth extraction. Forty patients referred for wisdom tooth impaction were selected. Before surgery, patients were randomly assigned to receive one of the following pharmacologic treatments: no medication (group 1), postextractive endoalveolar collagen sponge (group 2), systemic alendronate for 4 months starting the day of surgery (group 3), and group 2 + group 3 (group 4). Standardized orthopantomographic evaluation was obtained during recruitment (T1), immediately after surgery (T2), and 4 months (T3) to evaluate crestal and alveolar socket changes. Results indicate that at T2, crest and socket level did not show significant differences between the four groups. At T3, test sites treated showed less bone resorption compared with controls. In particular, higher vertical bone height levels and a faster intraalveolar healing were achieved in groups 3 and 4. Systemically given alendronate may be used successfully to reduce vertical bone resorption after wisdom tooth extraction.

A systematic review of the effectiveness of bone collectors.

PURPOSE: Bone collectors are used to harvest bone debris for grafting procedures during implant surgery. The particulate bone debris gathered through filtration has been frequently used in minor regenerative surgical procedures. Nevertheless, the biological potency of such grafts is still unclear. The objective of this study was to systematically review the use of bone collectors in implant dentistry, focusing on the quantity, quality, and bacterial contamination of the bone collected. MATERIALS AND METHODS: Following the production of a detailed protocol, screening and quality assessment of the literature were conducted in duplicate and independently. The outcome measures that were assessed were: (1) quantity of collected debris, (2) quality of the collected bone debris, and (3) bacterial contamination. RESULTS: There is a limited amount of information on the nature of bone obtained through collectors. Eleven studies satisfied the inclusion criteria. Bone collectors are able to retain a small amount of bone for minor surgical procedures. The presence of vital bone cells has not been demonstrated routinely, while consistent bacterial contamination has been observed. DISCUSSION: Bone collected through bone filters appears to be sufficient for small regenerative procedures. Clinicians should bear in mind that presence of bacterial pathogens is always shown with the use of bone collectors. Presurgical chlorhexidine oral rinsing and a strict aspiration protocol must be used to minimize the bacterial contamination of the debris collected. CONCLUSIONS: Although bone collectors are capable of amassing small amounts of bone, the vitality of this bone could not be consistently demonstrated and the collected debris was always contaminated by bacteria. Therefore, the bone debris amassed in bone collectors is not an ideal grafting material and should be utilized with caution.

Age-related changes of cell outgrowth from rat calvarial and mandibular bone in vitro.

AIM: To establish whether within an autograft ageing has an impact on the number of cells capable of responding to growth and differentiation factors released at defect sites. MATERIAL AND METHODS: The number of cells that grow out from calvarial and mandibular explants of rats 6 weeks and 9 months of age was evaluated and their response to mitogenic, chemotactic, and differentiation factors was characterized in vitro. The cell number was determined by automated counting, proliferation was evaluated by measuring the amount of (tritiated) (3)[H]thymidine incorporated into the DNA, and migration was assessed with the modified Boyden chamber assay. Alkaline phosphatase activity served as a marker of osteogenic differentiation. RESULTS: A confluent layer of cells was observed in mandibular and calvarial explant cultures derived from young rats within 10 days, while only sporadic cells were counted in cultures from adult animals. The number of cells derived from calvarial and mandibular bone of young rats was nine and five times higher, respectively, than that in explants from adult rats. Cells isolated from calvarial and mandibular explants responded to platelet-released supernatant by increased proliferation and migration in both age groups. Upon incubation with bone morphogenetic protein (BMP-6), the alkaline phosphatase activity of calvaria-derived cells from both age groups was higher than in unstimulated controls. Only one sample of cells derived from mandibular explants showed responsiveness to BMP-6 in the young age group, whereas none of the cell samples responded to BMP-6 in the adult age group. CONCLUSION: The number of cells capable of growing out from mandibular and calvarial grafts in vitro is lower in adult animals than in young animals. However, bone-derived cells from both young and adult rats respond to growth and differentiation factors present at defect sites, while there are topographic differences in the responsiveness to BMP-6.

Association between osteonecrosis of the jaws and chronic high-dosage intravenous bisphosphonates therapy.

Bisphosphonates (BPs) are used to inhibit bone resorption. Recently, they have been used in cancer patients to prevent bone loss due to bone metastasis. Fourteen consecutive patients, undergoing BPs monthly IV infusion due to neoplastic bone diseases, were diagnosed with osteonecrosis of the jaws. None of the patients had been previously undergoing radiotherapy of the head and neck region. Eight patients showed maxillary involvement, and nine patients had had a recent tooth extraction in the osteonecrosis areas. Biopsies and surgical debridment were performed. Histologically, none of the patients showed signs of bone metastasis. As high-dosage long-term BP therapy appears to be associated with osteonecrosis of the jaws, dental practitioners should exercise caution in the treatment of such patients.

Unusual asymptomatic giant sialolith of the submandibular gland: a clinical report.

This report presents an unusual case of asymptomatic sialolith of the submandibular gland. A 61-year-old man was referred to our department for multiple extractions. An ortopantomographic exam revealed the existence of a large radiopacity in the right premolar mandibular region. The patient was completely asymptomatic and no episodes of pain and swelling had occurred in the previous years. Ultrasonography and clinical examination confirmed the diagnosis of sialolithiasis of the submandibular duct. The calculus was removed trans-orally in local anaesthesia. The sialolith measured 22 mm and it was mainly constituted by phosphate, calcium and smaller amounts of magnesium. The bacteriological exam revealed the presence of Streptococcus Mitis, Streptococcus Salivarius and non-pathogenic Neisserie. Postoperative course was uneventful. Even a sialolith of significant dimensions may not be symptomatic. Nevertheless, the likelihood of future complications may constitute an indication for surgical removal of abnormal asymptomatic sialoliths.

Bone marrow stromal cells of young and adult rats respond similarly to platelet-released supernatant and bone morphogenetic protein-6 in vitro.

BACKGROUND: Age-related changes in periodontal bone regeneration, osseointegration of dental implants, and graft consolidation are increasingly considered in treatment planning. This study was intended to show whether aging is associated with a diminished responsiveness of osteoprogenitor cells to growth and differentiation factors. METHODS: We compared the capacity of bone marrow stromal cells harvested from young and adult rats to proliferate, migrate, and differentiate into the osteogenic lineage following exposure to platelet-released supernatant (PRS) or bone morphogenetic protein-6 (BMP-6). Bone marrow stromal cells were isolated from 12 young rats aged 6 weeks and 12 adult rats aged 9 months. Proliferation was assessed by 3[H]thymidine incorporation, migration was evaluated with the Boyden chamber assay, and osteogenic differentiation was deduced from alkaline phosphatase activity. RESULTS: Irrespective of the donor age, bone marrow stromal cells showed increased mitogenic activity and chemotactic motility when exposed to PRS. Adult bone marrow stromal cells had higher alkaline phosphatase activities at baseline and upon incubation with BMP-6 than cells obtained from young animals. There was no difference between the two groups in the slope of the alkaline phosphatase activity curve following stimulation with BMP-6. CONCLUSIONS: The data demonstrate that, irrespective of their age, bone marrow stromal cells respond similarly to PRS and BMP-6 under in vitro conditions. These findings suggest that osteoprogenitor cells within the bone marrow of adult rats retain their juvenile potential to respond to growth and differentiation factors, which are released naturally or are applied therapeutically at sites of bone regeneration.

The in vitro effect of different PRP concentrations on osteoblasts and fibroblasts.

OBJECTIVES: The aim of this study was to assess the biological rationale for the use of platelet-rich plasma (PRP) by evaluating the effect of different concentrations of PRP on osteoblasts (OB) and fibroblasts (FB) function in vitro. MATERIAL AND METHODS: PRP was obtained from volunteer donors using standard protocols. Primary human cultures of oral FBs and OBs were exposed to both activated and non-activated plasma as well as various concentrations of PRP (2.5 x, 3.5 x and max (4.2-5.5 x)). Cell proliferation was evaluated after 24 and 72 h using an MTT proliferation assay. Production of osteocalcin (OCN), osteoprotegerin (OPG) and transforming growth factor beta1 (TGF-beta1) was evaluated in OB after 24 and 72 h. Statistical analysis was performed using one-way ANOVA. RESULTS: PRP-stimulated cell proliferation in both OBs and FBs. The effect of different PRP concentrations on cell proliferation was most notable at 72 h. The maximum effect was achieved with a concentration of 2.5 x, with higher concentrations resulting in a reduction of cell proliferation. Upregulation of OCN levels and downregulation of OPG levels were noted with increasing PRP concentrations at both 24 and 72 h. TGF-beta1 levels were stimulated by increasing concentrations of PRP, with the increased levels being maintained at 72 h. CONCLUSIONS: PRP preparations exert a dose-specific effect on oral FBs and OBs. Optimal results were observed at a platelet concentration of 2.5 x, which was approximately half of the maximal concentrate that could be obtained. Increased concentrations resulted in a reduction in proliferation and a suboptimal effect on OB function. Hence, different PRP concentrations may have an impact on the results that can be obtained in vivo.

Cathepsin K levels in the crevicular fluid of dental implants: a pilot study.

OBJECTIVE: To determine the concentration of cathepsin K secreted into the crevicular fluid around dental implants and its correlation with clinical parameters of healthy implants and implants showing clinical signs of peri-implantitis. MATERIAL AND METHODS: Nineteen patients with 40 implants with and without peri-implantitis were enrolled in the study. Peri-implantitis was diagnosed by the pocket probing depth (PD), the modified bleeding index (MBI), the modified plaque index (MPI) and by radiographic signs of bone loss. Gingival crevicular fluid collected from the buccal and lingual sites was adsorbed to filter strips. Cathepsin K levels and total protein within the crevicular fluid were determined by immunoassay and the bicinchoninic method, respectively. RESULTS: Cathepsin K per filter strip normalized to the time of collection was 10.1 (0-33.5) pmol/sample around control implants and 22.4 (3.7-56.3) pmol/sample in the peri-implantitis group. The difference between the medians was significant (p < 0.01). Absolute cathepsin K levels in the crevicular fluid of all implants investigated showed a positive correlation with PD (R = 0.25; p = 0.03), MPI (R = 0.28; p = 0.01) and MBI (R = 0.32; p < 0.01). Absolute cathepsin K levels in the crevicular fluid also correlated with the adsorbed volume of gingival crevicular fluid (R = 0.51; p < 0.01). When normalized to the adsorbed volume of gingival crevicular fluid, the concentration of cathepsin K was 2.2 (0.01-6.4) nM around control implants and 1.7 (0.4-4.6) nM in the peri-implantitis group (p = 0.33). Patients' age correlated with sample volume and with cathepsin K normalized to the adsorbed volume of gingival crevicular fluid (R = 0.39; p < 0.01). Moreover, significant differences between male and female (p < 0.01, p < 0.01), and between mandible and maxilla (p < 0.05, p < 0.01), but not between buccal and lingual sites (p = 0.99, p= 0.93), were observed when analysed for the parameters adsorbed volume and absolute cathepsin K levels. CONCLUSION: Clinical parameters of peri-implantitis are associated with a higher amount of cathepsin K and a higher volume adsorbed to filters strips. To establish cathepsin K as a biochemical parameter to monitor peri-implant tissue health, age, sex and collection site should be considered to avoid interfering influences because of sample inhomogenity. Also a prospective study over time including more patients would be necessary.