Influence of mandibular residual ridge resorption on objective masticatory measures of lingualized and fully bilateral balanced denture articulation

PurposeTo assess the influence of mandibular residual ridge resorption (RRR) on objective masticatory measures of two occlusal schemes: lingualized occlusion (LO) and fully bilateral balanced articulation (FBBA).MethodsThe enrolled patients (n = 22) were randomly allocated one set of complete dentures with either LO or FBBA. Maximum occlusal force, masticatory performance (by the MPI), and mandibular movements were measured at 3- and 6-month follow-ups. Mandibular RRR was assessed as the sum of the mandibular bone height at the midline, first premolar region, and least vertical height region, and from the mental foramen to the alveolar crest, measured on panoramic radiographs; the treatment groups were subclassified into severe or moderate RRR subgroups by the value of the sum of individual measurements.ResultsSignificant differences were observed in the between-subgroup comparisons (Kruskal–Wallis test) of the MPI (3 months, p = 0.01; 6 months, p = 0.04) and linear deviation from intercuspal position (anterior–posterior: 6 months, p = 0.01; inferior–superior: 3 months, p = 0.008; 6 months, p = 0.02). The patients with severe RRR in the FBBA group showed a significant decrease in the MPI and increase in linear inferior deviation from intercuspal position at 3 months (post hoc comparison) as well as a significant increase in the linear posterior and inferior deviation from intercuspal position at 6 months.ConclusionsLO is the preferable occlusal scheme for patients with severe RRR. (This trial has been registered at http://clinicaltrials.gov/ct2/show/NCT00959530.)     

Effects of ovariectomy on periodontal tissues following tooth replantation

ObjectivesThe aim of the study was to analyze the effects of ovariectomy on periodontal tissues following immediate tooth replantation by histomorphometric, immunohistochemistry, and μCT analysis.Materials and methodsEighty wistar rats (Rattus norvegicus albinos) with normal estrous cycles were randomly divided into two groups: ovariectomized (OVX) and Sham. Two months after surgery, the rats’ upper right incisor was extracted followed by immediate reimplantation. The animals were sacrificed after 28, 45, and 60 days healing time. Histomorphometric and immunohistochemical analysis were performed by evaluation of PCNA and TRAP straining.ResultsThe periodontal ligament was reinserted into the bone and cementum in the both groups. The immunohistochemical analysis revealed PCNA positive cells on the periodontal ligament in both groups at 28 days. Root resorption was noted at 45 days with immunoreactive cells for TRAP present in bone and tooth surface however no statistical differences between the groups were noticed. Histomorphometric analysis showed significant difference between groups in the periodontal ligament and root resorption parameters for the sub-items: intensity of chronic inflammatory infiltrate at 60 days (p < 0.01), the organization of the periodontal ligament at 28 days (p < 0.05), depth of root resorption at 45 days (p < 0.05) and at 60 days (p < 0.001). The μCT analysis showed multiple areas of bone resorption in association with OVX at 28 and 60 days with no significant differences between times in vivo.ConclusionThe ovariectomy did not have significant influence in periodontal tissue parameters following tooth reimplantation.     

Effects of heat-inactivated Bifidobacterium BB12 on cariogenicity of Streptococcus mutans in vitro

ObjectiveSince some probiotic bacteria are cariogenic themselves, their suitability for caries management is questionable. Inactivated bacteria or their supernatants have been found to exert probiotic effects, whilst having several advantages compared with living bacteria. We hypothesized that viable and heat-inactivated Bifidobacterium animalis BB12 reduces the cariogenicity of Streptococcus mutans (SM) in vitro.DesignWe assessed mono- and mixed species biofilms of SM and viable or heat-inactivated BB12. Biofilms were grown in a continuous-culture-system under cariogenic conditions on smooth proximal enamel or cavitated dentine. For each of eight experimental subsets (4 biofilms × 2 hard-tissue conditions), a total of 32 specimens was used. After 10 days, bacterial numbers of 12 biofilms per group were analysed, and all specimens submitted to transversal microradiography.ResultsMineral loss was higher in cavitated dentine than smooth enamel for all biofilms (p < 0.001, t-test). BB12-monospecies biofilms induced significantly less mineral loss than SM in both enamel (p < 0.05) and dentine (p < 0.001). Viable BB12 did not significantly reduce cariogenicity of SM (p > 0.05), whilst heat-inactivated BB12 decreased cariogenicity of SM in dentinal cavities (p < 0.01). Bacterial numbers were higher on dentine than enamel (p < 0.05), but not significantly influenced by biofilm species (p > 0.05).ConclusionsHeat-inactivated BB12 reduced the cariogenicity of SM in dentinal cavities in vitro. Inactivated probiotics might be suitable for caries control.     

Association of the XPD and XRCC3 gene polymorphisms with oral squamous cell carcinoma in a Northeastern Brazilian population: A pilot study

Objectiveto evaluate the association between XPD and XRCC3 polymorphisms and oral squamous cell carcinoma (OSCC).Designthe sample consisted of 54 cases of OSCC and 40 cases of inflammatory fibrous hyperplasia (IFH). Genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.ResultsXPD-Lys/Gln was more common in IFH (n = 28; 70%) than in OSCC (n = 24; 44.4%) (OR: 0.3; p < 0.05). XPD-Gln was more frequent in high-grade lesions (0.48) than in low-grade lesions (0.21) (OR: 3.4; p < 0.05). The Gln/Gln genotype was associated with III and IV clinical stages (OR: 0.07; p < 0.05). XRCC3-Met was more frequent in OSCC (0.49) than in IFH (0.35) (OR: 2.6; p < 0.05). The Met/Met genotype was associated with the presence of metastases (OR: 8.1; p < 0.05) and with III and IV clinical stages (OR: 0.07; p < 0.05).Conclusionsin this sample, the frequency of XPD-Gln in IFH suggests that this variant may protect against OSCC. The presence of the XRCC3-Met allele seems to contribute to the development of OSCC, metastases and more advanced stages in these lesions.     

Effects of glucocorticoid-induced osteoporosis on bone tissue of rats with experimental periodontitis

ObjectiveTo evaluate the effects of osteoporosis induced by glucocorticoid (GIOP) on bone tissue of rats with experimental periodontitis (EP).Design48 male Wistar rats divided into groups: Naïve, EP, GIOP and GIOP + EP. Rats of GIOP and GIOP + EP groups received 7 mg/kg of dexamethasone intramuscularly once a week for 5 weeks. Following, EP and GIOP + EP groups were subjected to ligature-induced periodontitis. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic, radiographic, micro-tomographic and microscopic analysis of alveolar bone loss (ABL). Blood samples were collected for determination of bone-specific alkaline phosphatase (BALP) levels and the right femurs were removed for radiographic and biomechanical analysis.ResultsEP caused ABL and reduced BALP levels (p < 0,05), but it did not change the architecture or biomechanics of femur, compared to Naïve. GIOP did not cause ABL, but it significantly decreased alveolar bone mineral density (ABMD), bone percentage and trabecular thickness (Tb.Th) and increased alveolar bone porosity (p < 0.05) and significantly reduced BALP serum levels, as well as radiographic density and Young’s module of femur, compared to Naïve. There was a greater ABL in group GIOP + EP when compared to EP (p < 0.05). GIOP + EP caused a greater decrease on ABMD, Tb.Th, bone percentage and increased bone porosity (p < 0.05) and also presented a significant reduction in BALP levels (p < 0.05), in radiographic density and in Young’s module of femur compared to EP (p < 0.05).ConclusionsGIOP can potentiate the destructive effects of EP on alveolar bone and alter the systemic bone loss, by promoting bone resorption and reducing osteoblast activity.     

Extensive phenotyping of the orofacial and dental complex in Crouzon syndrome

ObjectivesFibroblast growth factor receptor 2 (FGFR2) ^C342Y/+ mutation is a known cause of Crouzon syndrome that is characterised by craniosynostosis and midfacial hypoplasia. Our aim was to conduct extensive phenotyping of the maxillary, mandibular and dental morphology associated with this mutation.Materials and methodsMorphometric data were obtained from 40 mice, representing two genotypes (Crouzon and wild-type) and two sexes (males and females) (n = 10 in each group). Dental analysis further categorised the first molars into the two jaws (maxillary and mandibular) (n = 20 in each group). Maxillary, mandibular and dental morphology was compared by analysing 23 linear landmark-based dimensions in three-dimensional micro-computed tomography reconstructions.ResultsCompared with wild-type, Crouzon (FGFR2^C342Y/+) maxillae were significantly shorter in maximum height, anterior and posterior lengths and middle width, but larger in posterior width (p < 0.05 for height; p < 0.001 for other comparisons). In the Crouzon mandible, the ascending and descending heights, effective and mandibular lengths, and intercoronoid and intercondylar widths were significantly shorter, whereas intergonial width was larger (p < 0.01 for intercondylar width; p < 0.001 for other comparisons). Crouzon teeth were significantly smaller mesiodistally, but larger in crown height (p < 0.001 for each comparison). All Crouzon mice presented with bifid mandibular condyles and a quarter presented with expansive bone lesions in the mandibular incisor alveolus.ConclusionsOur findings of hypoplasia in all three planes in Crouzon maxillae and mandibles, together with the presence of bifid mandibular condyles and expansive bone lesions, may be relevant to maxillofacial surgery and orthodontics. Beyond skeletal effects, the FGFR2^C342Y/+ mutation is now implicated in affecting tooth development. This study’s skeletal phenomics data also provides baseline data against which the effect of various treatments can now be assessed.     

Probiotic intervention influences the salivary levels of Matrix Metalloproteinase (MMP)-9 and Tissue Inhibitor of metalloproteinases (TIMP)-1 in healthy adults

ObjectiveTo study the effect of orally administered Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus rhamnosus GG on the salivary levels of Matrix Metalloproteinases (MMP)-8, MMP-9 and of Tissue Inhibitor of Metalloproteinases (TIMP)-1 in healthy adults. Furthermore, the correlations between MMP-8, MMP-9 and TIMP-1 and plaque and gingival indices, salivary mutans streptococci and lactobacilli counts, and stimulated saliva secretion rate were analysed.DesignThe salivary samples originated from a randomized controlled trial where healthy student volunteers consumed probiotic or placebo lozenges twice a day for four weeks. The saliva samples were collected and clinical parameters measured at the baseline and at the end of the original study. For this study, the salivary levels of MMP-8, MMP-9 and TIMP-1 were analysed with immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay (ELISA).ResultsIn the probiotic group (n = 29), salivary MMP-9 levels increased (p < 0.01) and TIMP-1 levels decreased (p < 0.01) significantly during the intervention. Furthermore, MMP-9/TIMP-1 ratio differed significantly from the baseline level (p < 0.01). These changes were not observed in the control group (n = 31). In the whole data, salivary MMP-9 and gingival index correlated (r = 0.260, p < 0.05 at baseline and r = 0.354, p < 0.01 at the end of the study). Intergroup differences or correlations with other clinical parameters were not found. Probiotic consumption did not affect the saliva flow rate.ConclusionsIncreased MMP-9 and decreased TIMP-1 levels in saliva may indicate that probiotics have immunomodulatory effects in the oral cavity. Furthermore, increased salivary MMP-9 levels may be an indication of the defensive potential of matrix metalloproteinases.     

Does smoking affect gingival crevicular fluid LL-37 levels following non-surgical periodontal treatment in chronic periodontitis?

ObjectiveLL-37 contributes to maintaining the balance between health and disease. Smoking is a risk factor for periodontitis that impairs neutrophil functions. The aim of the present study was to comparatively evaluate gingival crevicular fluid (GCF) LL-37 levels in smoker and non-smoker chronic periodontitis (CP) patients and controls, as well as the effect of non-surgical periodontal treatment on GCF LL-37 levels.DesignThirty-one CP patients (16 smokers, 15 non-smokers) and thirty-one controls (16 smokers, 15 non-smokers) were included in the study. CP patients received non-surgical treatment. GCF LL-37 levels and periodontal parameters were assessed at baseline, 1 and 3 months after completion of non-surgical periodontal treatment. GCF LL-37 levels were analyzed by ELISA.ResultsNo significant difference was observed in GCF LL-37 levels between smoker and non-smoker controls (p > 0.05). Smoker CP group had significantly lower GCF LL-37 level than non-smoker CP group at baseline (p < 0.05). GCF LL-37 levels significantly decreased in non-smoker CP group at first week, 1 and 3 months after completion of non-surgical periodontal treatment (p < 0.05) although no significant decrease in GCF LL-37 levels was observed in smoker CP group (p > 0.05). Periodontal parameters were correlated with GCF LL-37 levels in non-smoker CP group (p < 0.05), but not in smoker CP group (p > 0.05).ConclusionsGCF LL-37 levels do not seem to be affected from smoking in periodontal health. However, smoking might have a suppressive effect on GCF LL-37 levels in CP. Non-surgical treatment is effective in decreasing GCF LL-37 levels in non-smoker CP patients but not in smokers with CP.     

Effects of risedronate on osteoblastic cell cultures

ObjectiveBisphosphonates (BPs) have been widely used in the treatment of bone disorders due to their ability to modulate bone turnover. The biological mechanisms through BFs exert their effects on osteoclasts are well established. However, the role of BFs on the osteoblasts is controversial. The present study aimed to evaluate the effects of risedronate on osteoblastic cells.DesignMC3TE-E1 cells were exposed to risedronate at 0, 10⁻⁸, 10⁻⁶, 10⁻⁴, and 10⁻³ M. The following parameters were assayed: (1) cell proliferation by hemocytometer counting after 24, 48 and 72 h, (2) cell viability by MTT assay after 24, 48 and 72 h, (3) Type I Collagen quantification by ELISA after 24, 48 and 72 h, (3) alkaline phosphatase activity after 7 and 10 days and (4) matrix mineralization after 14 days.ResultsAfter 24 h, risedronate did not affect both cell proliferation and viability (p > 0.05). However, after 48 and 72 h, a decrease in cell proliferation and viability was detected in osteoblastic cultures exposed to risedronate at 10⁻⁴ and 10⁻³ M (p < 0.05). After 48 and 72 h, Type I Collagen synthesis was stimulated by risedronate at 10⁻⁴ M (p < 0.05). High levels of ALP activity were detected in cultures exposed to risedronate at 10⁻⁴ M after 7 and 10 days (p < 0.05). After 14 day, high calcium content was observed in cultures exposed to risedronate at 10⁻⁴ M (p > 0.05).ConclusionThese results indicated that risedronate can promote osteoblast differentiation.     

Tooth sensitivity and efficacy of in-office bleaching in restored teeth

ObjectivesThe aim of this clinical trial was to evaluate efficacy (BE) and tooth sensitivity (TS) of in-office bleaching with a 35% hydrogen peroxide (HP) in patients with aesthetic restorations.MethodsHydrogen peroxide 35% was applied in two sessions, of three 15 min applications, in 15 patients with upper anterior sound teeth (S) and 15 with aesthetic restorations (R). The colour was recorded at baseline, one week and 6 months after treatment completion. Patients recorded TS on a 0–4 scale. The BE was evaluated by two-way ANOVA and Tukey's tests (α = 0.05). The percentage of patients with TS was evaluated by Fisher's exact test and TS intensity of treatments was compared with Mann–Whitney U-test (α = 0.05).ResultsAll participants experienced TS at least once during treatment. Higher TS intensity was observed in R (1.5 [1/1.75]) compared to S (0.5 [0/1.25]) during the bleaching (p < 0.05). S and R demonstrated similar tooth colour enhancement compared to baseline (p < 0.05) and both presented colour stability after 6 months of evaluation (p > 0.05).ConclusionsThe in-office bleaching with 35% HP was effective in patients with aesthetic restorations, however, a higher intensity of TS was observed during the bleaching protocol.Clinical relevanceIn-office dental bleaching can be performed in patients with adhesive restorations promoting satisfactory results; however, it can promote higher intensity of sensitivity compared to patients with sound teeth.     

Antibacterial response of oral microcosm biofilm to nano-zinc oxide in adhesive resin

ObjectiveVarious nanoparticles are currently under investigation to impart biointeractivity for dental materials. This study aimed to: (1) formulate an experimental dental adhesive containing ZnO nanoparticles; (2) evaluate its chemical and mechanical properties; and (3) assess the antibacterial response against oral microcosm biofilm.MethodsNanosized ZnO was chemically and morphologically evaluated. ZnO was incorporated at 0 (G_CTRL), 2.5 (G_2.5%), 5 (G_5%) and 7.5 (G_5%) wt.% in an experimental dental adhesive. The adhesives were evaluated for the degree of conversion (DC), flexural strength (FS), and elastic modulus (E). The antibacterial activity was evaluated using a 48 h-microcosm biofilm model after the formation of acquired pellicle on samples’ surfaces. Colony-forming units (CFU), metabolic activity, and live/dead staining were assessed.ResultsNanosized ZnO presented characteristic peaks of Zn-O bonds, and the particles were arranged in agglomerates. The DC ranged from 62.21 (±1.05) % for G_Ctrl to 46.15 (±1.23) % for G_7.5% (p < 0.05). G_7.5% showed lower FS compared to all groups (p < 0.05). Despite achieving higher E (p < 0.05), G_2.5% did not show differences for G_Ctrl regarding the FS (p > 0.05). G_7.5% had lower CFU/mL compared to G_Ctrl for mutans streptococci (p < 0.05) and total microorganisms (p < 0.05), besides presenting lower metabolic activity (p < 0.05) and higher dead bacteria via biofilm staining.SignificanceThe dental adhesives' physicochemical properties were similar to commercial adhesives and in compliance with ISO recommendations. G_7.5% restricted the growth of oral microcosm biofilm without impairing the physicochemical performance.     

Effects of extreme cooling methods on mechanical properties and shear bond strength of bilayered porcelain/3Y-TZP specimens

ObjectivesThis study investigated the effect of extreme cooling methods on the flexural strength, reliability and shear bond strength of veneer porcelain for zirconia.MethodsVita VM9 porcelain was sintered on zirconia bar specimens and cooled by one of the following methods: inside a switched-off furnace (slow), at room temperature (normal) or immediately by compressed air (fast). Three-point flexural strength tests (FS) were performed on specimens with porcelain under tension (PT, n = 30) and zirconia under tension (ZT, n = 30). Shear bond strength tests (SBS, n = 15) were performed on cylindrical blocks of porcelain, which were applied on zirconia plates. Data were submitted to one-way ANOVA and Tukey's post hoc tests (p < 0.05). Weibull analysis was performed on the PT and ZT configurations.ResultsOne-way ANOVA for the PT configuration was significant, and Tukey's test revealed that fast cooling leads to significantly higher values (p < 0.01) than the other cooling methods. One-way ANOVA for the ZT configuration was not significant (p = 0.06). Weibull analysis showed that normal cooling had slightly higher reliability for both the PT and ZT configurations. Statistical tests showed that slow cooling decreased the SBS value (p < 0.01) and showed less adhesive fracture modes than the other cooling methods.Clinical SignificanceSlow cooling seems to affect the veneer resistance and adhesion to the zirconia core; however, the reliability of fast cooling was slightly lower than that of the other methods.     

Influence of implant scanbody material,position and operator on the accuracy of digital impression for complete-arch: A randomized in vitro trial

PurposeTo evaluate the influence of implant scanbody (ISB) material, position and operator on the accuracy of a confocal microscopy intraoral scanning (IOS) for complete-arch implant impression.MethodsAn edentulous maxillary model with 6 internal hexagonal connection analogues was scanned with an extraoral optical scanner to achieve a reference file. Three ISBs made of different materials (polyetheretherketone (Pk), titanium (T) and Pk with a titanium base (Pkt)) were scanned with IOS by 3 operators. The resulting 45 test files were aligned to the reference file with a best fit algorithm. Linear (ΔX, ΔY and ΔZ-axis) and angular deviations (ΔANGLE) were assessed. Absolute values of the linear discrepancies were summed up to obtain a global measure of linear absolute error (ΔASS). Influence of ISB material, position and operator was statistically assessed using the mixed general linear model.ResultsAt multivariate analysis, whenΔASS was considered as response variable, it was identified a significant influence of material (p < 0.0001) and position (p = 0.0009) while no significant operator effect was detected.When ΔANGLE was considered as response variable, material and position significantly influenced the expected ΔANGLE (p = 0.0232 and p < 0.0001) and no operator effect was identified.ConclusionsThe investigated IOS for complete-arch digital impression was influenced by the ISB material with peek reporting the best results on both linear and angular measurements followed by titanium, peek-titanium resulting as the less accurate. Implant angulation affected significantly the linear deviations while implant position the angular deviations. Operator did not show any significant effect on the IOS accuracy.     

Characterization of mouthguard materials: Physical and mechanical properties of commercialized products

ObjectivesContemporary mouthguard materials need to perform consistently over a wide range of possible temperatures (?20 to 40 °C). Therefore the specific aim of this study was to characterize commercialized mouthguard materials’ properties and investigate the effect of temperature on these properties.MethodsFive commercially representative thermoplastic mouthguard materials (Essix? Resin, Erkoflex?, Proform?-regular, Proform?-laminate, and Polyshok?) were tested. The durometer hardness, water absorption, tear strength, and impact attenuation of the mouthguard materials were measured according to ASTM D2240-05, D570-98 (2005), D624-00, and ASTM D6110-06f (modified) guidelines. Tests were conducted on five separate specimens at both room 23 ± 2 °C and intra-oral 37 ± 2 °C temperatures. Independent t-tests (α = 0.05) were used to test for differences between room and intra-oral temperatures.ResultsMaterial hardness decreased (p < 0.05) from room to intra-oral temperatures for all mouthguard materials. Water absorption increased (p < 0.05) from room to intra-oral temperatures for all mouthguard materials. Tear strength decreased (p < 0.05) from room to intra-oral temperatures for all mouthguard materials. Impact attenuation between room and intra-oral temperatures was different (p < 0.05) for the Erkoflex?, Proform?-laminate, and Polyshok? material respectfully. However, there was no difference between temperatures for the Essix? Resin (p = .058) or Proform?-regular (p = .275) materials.SignificanceTemperature measureably affects the physical and mechanical properties of mouthguard materials. It is particularly noteworthy that none of the commercialized products met current ANSI and SAI standards for impact attenuation.     

The effect of initial periodontal treatment on plasma,gingival crevicular fluid and salivary levels of 8-hydroxy-deoxyguanosine in obesity

ObjectiveRecent studies have shown adverse effects on the periodontium from the increased production of reactive oxygen species (ROS) in obesity. The purpose of this study was to investigate the effects of obesity on 8-hydroxy-deoxyguanosine (8-OHdG) levels in the bodily fluids of patients with and without periodontal disease and to evaluate changes after initial periodontal treatment.DesignForty-five obese individuals and 45 normal-weight individuals were included in this study. Obese and normal-weight groups were classified into three sub-groups: chronic periodontitis (CP), gingivitis (G) and periodontally healthy controls (CTRL). Gingival crevicular fluid (GCF), plasma, saliva samples and clinical measurements were obtained at baseline and a month after initial periodontal treatment. Levels of 8-OHdG were analysed by ELISA.ResultsWhile plasma 8-OHdG levels were significantly higher at baseline in the obese patients with periodontal disease than in the normal-weight individuals (P < 0.05), no significant differences in GCF and saliva 8-OHdG levels were found (P ˃ 0.05). GCF and salivary 8-OHdG levels in obese patients with G and CP were significantly higher than in CTRL groups at baseline (P < 0.05). After treatment, 8-OHdG levels were decreased in all groups with periodontal disease (P < 0.01). Statistically significant positive correlations were observed between GCF 8-OHdG levels and GI in all the groups (P < 0.001).ConclusionsThe significant increase of plasma 8-OHdG levels in obese patients did not correlate with saliva and GCF 8-OHdG levels when compared to normal-weight individuals. Periodontal treatment had a positive effect on the periodontal parameters and 8-OHdG levels of both obese and normal-weight individuals.     

Effects of autogenous growth factors on heterotopic bone formation of osteogenic cells in small animal model

AimsThis study used a new approach to investigate the effective concentrations of growth factors released from platelet concentrate (PC) on the bone formation capacity of osteogenically differentiated rat bone marrow stromal cells (rBMSCs).Materials and methodsRat BMSCs and whole blood were harvested from 40 adult male Spraque-Dawly rats. Rat BMSCs were expanded in an osteogenic medium and seeded on inert collagenous bovine bone matrix (ICBM). Growth factors released from degranulated PC (GFs) containing TGF-β1 1 (25 ng/ml)–10 ng (250 ng/ml) and rhBMP-2 400 ng (10 μg/ml) were suspended in 40 μl platelet poor plasma (PPP) and applied on the ICBM–rBMSC constructs or ICBM only, respectively. The constructs were then transplanted in autologous hosts for 4 weeks. Concurrently, osteoblastic differentiation of rBMSCs on ICBM–rBMSC–PPP constructs was characterized in vitro.ResultsRat BMSCs in osteogenic medium exhibited phenotypes of mature osteoblasts. The amount of newly formed bone among groups of ICBM–rBMSC–PPP with and without GFs was not significantly different (p > 0.05) and was significantly lower than a group of ICBM–PPP–BMP-2 (p < 0.05).ConclusionsAutogenous GFs had no effect on the capacity of rBMSCs to form new bone. The ability to measure the bone formation capacity of transplanted autologous cells and growth factors in a small animal model was demonstrated.     

Study of the participation of MMP-7, EMMPRIN and cyclophilin A in the pathogenesis of periodontal disease

Background and objectivePeriodontal disease is an infectious disease resulting from the immunoinflammatory response of the host to microorganisms present in the dental biofilm which causes tissue destruction. The objective of this study was to evaluate the immunohistochemical expression of matrix metalloproteinase 7 (MMP-7), extracellular matrix metalloproteinase inducer (EMMPRIN) and cyclophilin A (CypA) in periodontal disease.DesignGingival tissue samples were divided as follows: clinically healthy gingiva (n = 32), biofilm-induced gingivitis (n = 28), and chronic periodontitis (n = 30). Histological sections of 3 μm were submitted to immunoperoxidase method and undergone quantitative analysis. The results were analyzed statistically by the Mann-Whitney and Spearman correlation tests, with the level of significance set at 0.05 (α = 0.05).ResultsImmunopositivity for MMP-7, EMMPRIN and CypA differed significantly between the three groups, with higher percentages of staining in chronic periodontitis specimens, followed by chronic gingivitis and healthy gingiva specimens (p < 0.05). Immunoexpression of CypA and MMP-7 was higher in the intense inflammatory infiltrate observed mainly in cases of periodontitis (p < 0.05). CypA expression was positively correlated with MMP-7 (r = 0.831; p < 0.001) and EMMPRIN (r = 0.289; p = 0.006). In addition, there was a significant positive correlation between probing depth and expression of MMP-7 (r = 0.726; p < 0.001), EMMPRIN (r = 0.345; p = 0.001), and CypA (r = 0.803; p < 0.001).ConclusionThese results suggest that MMP-7, EMMPRIN and CypA are associated with the pathogenesis and progression of periodontal disease.     

Deleterious effect of chronic continuous hypoxia on oral health

ObjectiveTo evaluate the effect of chronic continuous hypoxia (CCH) in alveolar bone and its correlation with the inflammatory markers which play a key role in the development of periodontitis.Material and methodsWistar rats were exposed to CCH (600 mbar, 3 months). Macroscopic and histological analyses of alveolar bone were performed, together with measurement of oxidative stress and inflammatory parameters in gums and submandibular glands (SMG).ResultsHCC induced cortical alveolar bone loss, decreased interradicular bone volume and increased the periodontal ligament height compared to control rats (p < 0.05). CCH enhanced iNOS activity in gums (from 2735,04 ± 662,96 nmol/min/mg proteins to 4289,58 ± 915,63 p < 0.05) and in SMG (from 56,71 ± 12,05 nmol/min/mg proteins to 90,15 ± 21,78 p < 0.05). PGE₂ did not change in gums or in SMG by means of CCH, while TNFα decreased in gums (p < 0.05). Regarding oxidative stress, thiobarbituric acid reactive species concentration in CCH animals was higher both in gums as in SMG, and catalase activity was decreased in SMG.ConclusionHigher iNOS activity both in gums and SMG under CCH could be associated with the alveolar bone loss observed. The increase in oxidative stress occurring in SMG and gums, together with a lower antioxidant capacity might indicate a deleterious effect of HX in oral health.     

Frequency of periodontal pathogens in equivalent peri-implant and periodontal clinical statuses

ObjectivesThis study tested the hypotheses that there is: (1) higher bacterial frequency in peri-implantitis/periodontitis, followed by mucositis/gingivitis and peri-implant/periodontal health; (2) similar bacterial frequency between comparable peri-implant and periodontal clinical statuses.Design of studyThe presence of Porphyromonas gingivalis, Tannerella forsythia, Campylobacter rectus, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans was evaluated in peri-implant (n = 53) and periodontal (n = 53) health; mucositis (n = 50), gingivitis (n = 50), peri-implantitis (n = 50) and periodontitis (n = 50).ResultsThe pattern of peri-implant bacterial frequency was not as expected (peri-implantitis > mucositis > health). Except for P. intermedia (p > 0.05), bacterial frequency was higher in peri-implantitis than health (p < 0.05). The frequency of P.gingivalis and red complex species were higher in peri-implantitis than mucositis (p < 0.05). In periodontal samples, T. forsythia and T. denticola showed the expected pattern of frequency (periodontitis > gingivitis > health). The frequencies of C. rectus and T. forsythia were higher in healthy teeth/gingivitis than healthy implants/mucositis, respectively (p < 0.05). The frequency of P. gingivalis and A. actinomycetemcomitans were similar between periodontitis and peri-implantitis (p > 0.05) while all other species occurrences were higher in periodontitis than peri-implantitis (p < 0.05).ConclusionsBacterial frequency increased from peri-implant/periodontal health to peri-implantitis/periodontitis but not from mucositis/gingivitis to peri-implantitis/periodontitis. There was a trend towards higher bacterial frequency in teeth than implants.