Porphyromonas gingivalis amount in the tongue biofilm is associated with erosive arthritis in systemic lupus erythematosus.

BACKGROUND: Several data have demonstrated the occurrence of erosive arthritis in Systemic Lupus Erythematosus (SLE) patients. However, a few studies have focused on the pathogenic mechanisms involved in this feature. The implication of oral pathogens has been proved in Rheumatoid Arthritis: in particular, Porphyromonas gingivalis (Pg), by inducing citrullination, could trigger autoimmune response. Here, we evaluated amount of Pg on the tongue in a cohort of SLE patients with arthritis, focusing on the association with the erosive phenotype. METHODS: SLE patients with arthritis were enrolled. DAS28 was applied to assess activity. Erosive damage was evaluated by ultrasound at level of MCP (metacarpophalangeal) and PIP (proximal interphalangeals) joints. All subjects underwent a tongue cytologic swab in order to quantify the amount of Pg (real-time PCR). The bacterium expression was obtained from the ratio between the patient's DNA amount and that obtained from healthy subjects. RESULTS: 33 patients were enrolled (M/F 3/30; median age 47 years, IQR 17; median disease duration 216 months, IQR 180): 12 of them (36.4%) showed erosive damage, significantly associated with ACPA positivity (p = 0.03) and higher values of DAS28 (p = 0.01). A mean ratio of 19.7 ± 31.1 was found for Pg amount. Therefore, we used Pg mean values as threshold, identifying two groups of patients, namely, highPg and lowPg. Erosive damage was significantly more frequent in highPg patients in comparison with lowPg (60.0% vs 26.0%, p = 0.001). Furthermore, highPg patients showed higher prevalence of skin manifestations, serositis, and neurological involvement (p = 0.005, p = 0.03, p = 0.0001, respectively). CONCLUSION: The possible contribution of oral microbiota in SLE erosive arthritis was here evaluated for the first time, finding a significant association between erosive damage and higher expression of Pg at tongue level.

Implementation of a software application in staging and grading of periodontitis cases.

OBJECTIVES: The purpose of this study was to assess the diagnostic accuracy and the inter-rater agreement among general dentists when staging and grading periodontitis cases with the aid of a software application (SA) developed by the Italian Society of Periodontology and Implantology. MATERIALS AND METHODS: Ten general dentists were asked to independently assess 25 periodontitis cases using the SA. Accuracy was estimated using quadratic weighted kappa and examiners' percentage of agreement with a reference diagnosis provided by a gold standard examiner. Inter-rater agreement was evaluated using Fleiss kappa statistics. RESULTS: The overall case definition agreed with the reference diagnosis in 53.6% of cases. The agreements for each general dentist's pairwise comparisons against the reference definition were at least substantial in 100% of cases for stage, in 70% of cases for grade and in none of the cases for extent. Fleiss kappa was 0.818, 0.608, and 0.632 for stage, extent, and grade, respectively. The study recognized possible reasons that could lead to decreased accuracy using the SA. CONCLUSIONS: Supported by the SA, general dentists have reached substantial inter-rater agreement and highly accurate assignments of stage and grade. However, complete case definitions were correctly diagnosed in slightly over half of the cases.

Flapless application of enamel matrix derivative in periodontal retreatment: A multicentre randomized feasibility trial.

AIM: To investigate the potential benefit of enamel matrix derivative (EMD) as adjunct to re-instrumentation of residual pockets persisting after steps 1 and 2 of periodontal therapy. MATERIAL AND METHODS: 44 adult patients participated in a multicentre feasibility randomized clinical trial with split-mouth design. They had presented at re-evaluation after initial non-surgical periodontal therapy (steps 1 and 2 of periodontal therapy) for generalized periodontitis with at least 2 teeth with residual probing pocket depths (PPD) ≥5 and ≤8 mm, with bleeding on probing (BOP). Two teeth with similar PPD were randomized to receive re-instrumentation either with (test) or without (control) adjunctive flapless administration of EMD. Differences in the changes of PPD and BOP from baseline to 6 and 12 months were analysed, and the frequencies of pocket closure (PPD ≤4 mm and no BOP) compared. RESULTS: For the primary outcome "change of mean PPD after 6 months," a significant additional benefit of 0.79 ± 1.3 mm (p < .0001) could be observed for the test group. At 12 months, this difference could be maintained (0.85 ± 1.1 mm; p < .0001). The frequency of pocket closure in the test group was 69% at 6 and 80% at 12 months and significantly higher than in the control group with 34% and 42%, respectively (p < .01). CONCLUSIONS: The results of the present feasibility study indicate a benefit of adjunctive EMD during non-surgical retreatment (step 3 of periodontal therapy) of residual deep pockets.

Gene expression profiles of oral soft tissue-derived fibroblast from healing wounds: correlation with clinical outcome, autophagy activation and fibrotic markers expression.

AIM: Our aim was to evaluate gene expression profiling of fibroblasts from human alveolar mucosa (M), buccal attached gingiva (G) and palatal (P) tissues during early wound healing, correlating it with clinical response. MATERIALS AND METHODS: M, G and P biopsies were harvested from six patients at baseline and 24 hr after surgery. Clinical response was evaluated through Early wound Healing Score (EHS). Fibrotic markers expression and autophagy were assessed on fibroblasts isolated from those tissues by Western blot and qRT-PCR. Fibroblasts from two patients were subjected to RT2 profiler array, followed by network analysis of the differentially expressed genes. The expression of key genes was validated with qRT-PCR on all patients. RESULTS: At 24 hr after surgery, EHS was higher in P and G than in M. In line with our clinical results, no autophagy and myofibroblast differentiation were observed in G and P. We observed significant variations in mRNA expression of key genes: RAC1, SERPINE1 and TIMP1, involved in scar formation; CDH1, ITGA4 and ITGB5, contributing to myofibroblast differentiation; and IL6 and CXCL1, involved in inflammation. CONCLUSIONS: We identified some genes involved in periodontal soft tissue clinical outcome, providing novel insights into the molecular mechanisms of oral repair (ClinicalTrial.gov-NCT04202822).

The staging and grading system in defining periodontitis cases: consistency and accuracy amongst periodontal experts, general dentists and undergraduate students.

AIM: The objective of this study was to evaluate consistency and accuracy of the periodontitis staging and grading classification system. METHODS: Thirty participants (10 periodontal experts, 10 general dentists and 10 undergraduate students) and a gold-standard examiner were asked to classify 25 fully documented periodontitis cases twice. Fleiss kappa was used to estimate consistency across examiners. Intraclass correlation coefficient (ICC) was used to calculate consistency across time. Quadratic weighted kappa and percentage of complete agreement versus gold standard were computed to assess accuracy. RESULTS: Fleiss kappa for stage, extent and grade were 0.48, 0.37 and 0.45 respectively. The highest ICC was provided by students for stage (0.91), whereas the lowest ICC by general dentists for extent (0.79). Pairwise comparisons against gold standard showed mean value of kappa >0.81 for stage and >0.41 for grade and extent. Agreement with the gold standard for all three components of the case definition was achieved in 47.2% of cases. The study identified specific factors associated with lower consistency and accuracy. CONCLUSIONS: Diagnosis was highly consistent across time and moderately between examiners. Accuracy was almost perfect for stage and moderate for grade and extent. Additional efforts are required to improve training of general dentists.

Healing of intrabony defects following regenerative surgery by means of single-flap approach in conjunction with either hyaluronic acid or an enamel matrix derivative: a 24-month randomized controlled clinical trial.

OBJECTIVES: The aim of this randomized controlled clinical trial was to compare the clinical outcomes obtained in intrabony defects following regenerative periodontal surgery using the single-flap approach (SFA) in conjunction with either hyaluronic acid (HA) or enamel matrix derivative (EMD). MATERIALS AND METHODS: Thirty-two intrabony defects in 32 healthy subjects were randomly assigned: HA (test group) or EMD (control group). Clinical attachment level (CAL), probing depth (PD), gingival recession (REC), and bleeding on probing (BOP) were recorded at baseline,12, 18, and 24 months after surgery. RESULTS: At 24 months, both treatments resulted in statistically significant clinical improvements evidenced by PD-reduction and CAL-gain (p<0.001). The mean CAL-gain was 2.19±1.11 mm in the test and 2.94±1.12 mm in the control sites (p=0.067). PD-reduction was statistically significantly higher for the control group (4.5±0.97 mm) than the test group (3.31±0.70 mm), (p=0.001). CAL-gain ≤ 3 mm was observed in 87.5% and in 62.5% of the test and control sites, respectively. Test sites showed slightly lower REC values than the control sites. No statistically significant differences were found for BOP between treatments. CONCLUSIONS: The present findings indicate that both treatments led to statistically significant clinical improvements compared to baseline, although the application of EMD resulted in statistically significantly higher PD-reduction compared to the use of HA. CLINICAL RELEVANCE: The use of HA in conjunction with a SFA resulted in significant PD-reduction and CAL-gain, pointing to the potential clinical relevance of this material in regenerative periodontal surgery.

Coronally advanced flap and composite restoration of the enamel with or without connective tissue graft for the treatment of single maxillary gingival recession with non-carious cervical lesion. A randomized controlled clinical trial.

BACKGROUND: Aim of this study was to compare coronally advanced flap (CAF) and composite restoration of the cement-enamel junction (CEJ) with or without connective tissue graft (CTG) for treatment of single maxillary gingival recession with non-carious cervical lesion (NCCL). MATERIAL AND METHODS: Thirty patients with single gingival recessions and previously restored NCCL were randomly allocated to the two groups. A masked examiner evaluated recession reduction (RecRed), complete root coverage (CRC), keratinized tissue (KT) gain, increase in gingival thickness (GT), patient satisfaction and Root coverage Esthetic Score (RES). RESULTS: No significant difference for RecRed and CRC was detected at 12 months. CAF + CTG resulted in greater increase of KT width and thickness (p < .001). An interaction between baseline GT and type of treatment was reported, suggesting that when baseline GT was ≤0.84 mm adding CTG led to higher RecRed, while for values >0.84 mm the use of CAF was associated with better outcomes. Similarly, CAF alone provided better final RES score for baseline GT > 0.82 mm. CONCLUSION: Both procedures were effective for root coverage at single RT1 recession with previously restored CEJ. Adding a CTG under CAF should be considered for Rec with thin gingival phenotype.

Porphyromonas gingivalis and rheumatoid arthritis.

PURPOSE OF REVIEW: To explore the pathogenic association between periodontal disease and rheumatoid arthritis focusing on the role of Porphyromonas gingivalis. RECENT FINDINGS: In the last decades our knowledge about the pathogenesis of rheumatoid arthritis substantially changed. Several evidences demonstrated that the initial production of autoantibodies is not localized in the joint, rather in other immunological-active sites. A central role seems to be played by periodontal disease, in particular because of the ability of P. gingivalis to induce citrullination, the posttranslational modification leading to the production of anticitrullinated protein/peptide antibodies, the most sensitive and specific rheumatoid arthritis biomarker. SUMMARY: The pathogenic role of P. gingivalis has been demonstrated in mouse models in which arthritis was either triggered or worsened in infected animals. P. gingivalis showed its detrimental role not only by inducing citrullination but also by means of other key mechanisms including induction of NETosis, osteoclastogenesis, and Th17 proinflammatory response leading to bone damage and systemic inflammation.

Periodontitis and Rheumatoid Arthritis: The Same Inflammatory Mediators?

The strict link between periodontitis (PD) and rheumatoid arthritis (RA) has been widely demonstrated by several studies. PD is significantly more frequent in RA patients in comparison with healthy subjects: this prevalence is higher in individuals at the earliest stages of disease and in seropositive patients. This is probably related to the role of P. gingivalis in inducing citrullination and leading to the development of the new antigens. Despite the many studies conducted on this topic, there is very little data available concerning the possibility to use the same biomarkers to evaluate both RA and PD patients. The aim of the review is to summarize this issue. Starting from genetic factors, data from literature demonstrated the association between HLA-DRB1 alleles and PD susceptibility, similar to RA patients; moreover, SE-positive patients showed simultaneously structural damage to the wrist and periodontal sites. Contrasting results are available concerning other genetic polymorphisms. Moreover, the possible role of proinflammatory cytokines, such as TNF and IL6 and autoantibodies, specifically anticyclic citrullinated peptide antibodies, has been examined, suggesting the need to perform further studies to better define this issue.

Effectiveness of adjunctive hyaluronic acid application in coronally advanced flap in Miller class I single gingival recession sites: a randomized controlled clinical trial.

OBJECTIVES: The aim of this randomized controlled clinical trial was to evaluate the possible advantages of adjunctive hyaluronic acid (HA) application in the coronally advanced flap (CAF) procedure in single Miller class I/recession type 1 (RT1) gingival recession treatment. MATERIAL AND METHODS: Thirty patients with one recession were enrolled; 15 were randomly assigned CAF + HA and 15 to CAF alone. The recession reduction (RecRed), clinical attachment level gain (CAL-gain), changes in probing pocket depth (PPD) and in the width of keratinized tissue (KT), complete root coverage (CRC), and mean root coverage (MRC) were calculated after 18 months. Post-operative morbidity (pain intensity, discomfort, and swelling) was recorded 7 days after treatment using visual analogue scale (VAS). RESULTS: After 18 months, RecRed was statistically significantly higher in the test group (2.7 mm [1.0]) than in the control group (1.9 mm [1.0]; p = 0.007). PPD were found to be slightly but statistically significantly increased in both groups. No statistically significant difference was found for KT gain between treatments. CRC was 80% for test and 33.3% for control sites (p < 0.05). A MRC of 93.8 ± 13.0% for test and 73.1 ± 20.8% for control sites was calculated (p < 0.05). The test group reported lower swelling and discomfort values 7-days post-surgery (p < 0.05). Statistically significant difference was not found for pain intensity. CONCLUSIONS: The adjunctive use of HA was effective in obtaining CRC for single Miller class I/RT1 gingival recession sites. CLINICAL RELEVANCE: Adjunctive application of HA in the coronally advanced flap procedure may improve the reduction of the recessions and increase the probability of CRC in Miller class I recessions.

Correction to: Effectiveness of adjunctive hyaluronic acid application in coronally advanced flap in Miller class I single gingival recession sites: a randomized controlled clinical trial.

The figure 2 of the original version of this article was incorrect. Correct figure is presented below.

Adjunctive efficacy of probiotics in the treatment of experimental peri-implant mucositis with mechanical and photodynamic therapy: a randomized, cross-over clinical trial.

AIM: To evaluate the adjunctive clinical efficacy of probiotics in the treatment of peri-implant mucositis (p-iM) with professionally administered plaque removal (PAPR) and photodynamic therapy (PDT). MATERIALS AND METHODS: Following p-iM induction, patients underwent PAPR + PDT and were randomly assigned to receive the professional and home-based administration of probiotics (Lactobacillus plantarum and Lactobacillus brevis) (test treatment) or placebo preparation (control treatment) according to a cross-over design. Clinical parameters were assessed at six sites for each implant before as well as at 2 and 6 weeks after professional treatment administration. RESULTS: Twenty patients contributing one dental implant each were included. Immediately before treatment and at 6 weeks, the median number of sites with bleeding on probing (BoP+) sites per implant unit was 4 (3-6) and 2 (0-2) (p < 0.001), respectively, for test treatment, and 3.5 (2-4) and 2 (0-3) (p = 0.03), respectively, for control treatment. No significant difference in clinical outcomes was observed between treatment groups. CONCLUSION: The combination of PAPR and PDT either alone or associated with probiotics determined a significant reduction in the number of BoP+ sites at 2 and 6 weeks around implants with p-iM. The adjunctive use of probiotics did not significantly enhance the clinical outcomes of PAPR + PDT.

Autophagy activation is required for myofibroblast differentiation during healing of oral mucosa.

AIM: It is known that periodontal tissues heal faster that skin, and gingiva in particular heal without scar formation. The mechanisms regulating this behaviour are still unclear. The aim of our work was to compare wound healing in oral mucosa and gingiva, investigating the role of α-smooth muscle actin (αSMA)-expressing myofibroblasts and autophagy. MATERIALS AND METHODS: Biopsies were obtained from seven patients immediately before and 24 hr after vertical releasing incision in oral mucosa and attached gingiva. Both whole biopsies and primary cultures of fibroblasts derived from the same tissues were subjected to immunofluorescence, Western blot and quantitative real-time PCR analyses. RESULTS: We demonstrated that in oral mucosa, characterized by partially fibrotic outcome during repair, the activation of autophagy determined an increase in αSMA and collagen 1a1 production. Conversely, wound healing did not stimulate autophagy in attached gingiva, and subsequently, no increase in myofibroblast differentiation and collagen deposition could be seen, thus justifying its scarless outcome. CONCLUSIONS: The elucidation of the differential regulation of autophagy in periodontal tissues and its correlation with myofibroblast differentiation and fibrotic outcome could allow the identification of new molecules involved in periodontal healing and the development of new surgical approaches for periodontal treatment that could improve the outcome of postoperative wounds.

Clinical efficacy of coronally advanced flap with or without connective tissue graft for the treatment of multiple adjacent gingival recessions in the aesthetic area: a randomized controlled clinical trial.

BACKGROUND: The aim of this study was to assess the clinical efficacy of coronally advanced flap (CAF) with or without connective tissue graft (CTG) for the treatment of multiple adjacent gingival recessions in the upper arch. MATERIAL AND METHODS: Thirty-two patients with a total of 74 gingival recessions were randomly allocated to the two groups. Outcome measures, collected by a blind examiner, included complete root coverage (CRC), recession reduction (RecRed), keratinized tissue (KT) gain, increase in gingival thickness (GT), patient satisfaction and root coverage esthetic score (RES). RESULTS: An interaction between treatment and baseline GT was detected. At 1 year, CAF + CTG resulted in better outcomes in terms of CRC (p = 0.0016) and RecRed (p < 0.0001) than CAF alone at sites with thin gingiva (thickness ≤ 0.8 mm). No difference was found between CAF alone and CAF + CTG at sites with thick gingiva (>0.8 mm). CAF resulted in higher aesthetic scores (RES) than CAF + CTG at sites with thick gingiva. CAF + CTG was associated with greater KT gain (p < 0.0001) and greater post-operative morbidity (p < 0.0001). CONCLUSION: Connective tissue graft under CAF results in increased probability of CRC only at sites with thin baseline gingiva. CAF alone is associated with similar clinical outcomes and better aesthetics at sites with thick baseline gingiva.

Light-activated disinfection using a light-emitting diode lamp in the red spectrum: clinical and microbiological short-term findings on periodontitis patients in maintenance. A randomized controlled split-mouth clinical trial.

Eradication or suppression of pathogens is a major goal in periodontal therapy. Due to the increase in antibiotic resistance, the need of new disinfection therapies is raising. Photodynamic therapy (PDT) has demonstrated anti-infective potential. No data are available on the use of light-emitting diode (LED) lights as the light source in PDT. The aim of this study was to investigate the microbiological and clinical adjunctive outcome of a new photodynamic LED device, compared to scaling and root planing in periodontitis patients in maintenance [supportive periodontal therapy (SPT)]. In this masked, split-mouth design study, 30 treated chronic periodontitis subjects (mean age, 46.2 years; 13 males) in SPT were included. Two residual interdental sites with probing pocket depth (PPD) ≥ 5 mm in two opposite quadrants, with positive bleeding on probing (BOP) and comparable periodontal breakdown, were selected. PPD, BOP and subgingival microbiological samples for real-time PCR analysis (Carpegen® PerioDiagnostics, Carpegen GmbH, Münster, Germany) were recorded at baseline and 1 week after treatment. Scaling and root planing was performed under local anesthesia. Randomly one of the sites was selected to receive adjunctive photodynamic therapy by inserting a photosensitizer (toluidine blue O solution) and exposing it to a LED light in the red spectrum (Fotosan, CMS Dental, Copenhagen, Denmark), according to the manufacturer's instructions. After 1 week, 73 % of the control sites and 27 % of the test sites were still BOP+. These differences compared to baseline values and in-between groups were statistically significantly different (p < 0.001). Mean PPD decreased from 5.47 mm (±0.68) to 4.73 mm (±0.74, p < 0.001) in control sites and from 5.63 mm (±0.85) to 4.43 mm (±1.25, p < 0.001, test vs control p = 0.01) in the test group. Microbiologically, higher reductions of relative proportions of red complex bacteria were observed in test sites (68.1 vs. 4.1 %; p = 0.01). This study showed that adjunctive photodynamic treatment by LED light may enhance short-term clinical and microbiological outcome in periodontitis subjects in SPT.

Analysis of human alveolar osteoblast behavior on a nano-hydroxyapatite substrate: an in vitro study.

BACKGROUND: Nano-hydroxyapatite (nHA) is a potential ideal biomaterial for bone regeneration. However, studies have yet to characterize the behavior of human osteoblasts derived from alveolar bone on nHA. Thus, the aim of the present study was to evaluate the influence of nHA on the adhesion, proliferation and differentiation of these alveolar bone-derived cells. METHODS: Primary human alveolar osteoblasts were collected from the alveolar ridge of a male periodontal patient during osseous resective surgery and grown on culture plates coated with either polylysine or polylysine with nano-hydroxyapatite (POL/nHA) composite. The cells were grown and observed for 14 days, and then assessed for potential modifications to osteoblasts homeostasis as evaluated by quantitative reverse transcriptase-polymerase chain reaction (real time RT-PCR), scanning electron microscopy and atomic force microscopy. RESULTS: Real time PCR revealed a significant increase in the expression of the selected markers of osteoblast differentiation (bone morphogenetic protein (BMP)-2,-5,-7, ALP, COLL-1A2, OC, ON) in cells grown on the POL/nHA substrate. In addition, as compared with the POL surface, cells grown on the POL/nHA substrate demonstrated better osteoconductive properties, as demonstrated by the increase in adhesion and spreading, likely as a result of the increased surface roughness of the composite. CONCLUSIONS: The increased expression of BMPs and osteoinductive biomarkers suggest that nano-hydroxyapatite may stimulate the proliferation and differentiation of local alveolar osteoblasts and thus encourage bone regeneration at sites of alveolar bone regeneration.

The mucosal released-coronally advanced flap: A novel surgical approach-A case report.

BACKGROUND: The coronally advanced flap (CAF) can be a predictable surgical technique for the treatment of gingival recessions. However, the characteristics of the defect (e.g., limited amount of keratinized gingiva or flap tension, etc.) may limit the use of the CAF with a possible requirement of additional surgical interventions (i.e., the use of a tissue graft to be harvested from donor sites or connective tissue substitutes). METHODS: A 28-year-old woman patient, with no history of periodontal disease, came for referral presenting receding gums as a chief complaint, poor esthetics, and dentinal hypersensitivity at the buccal surface of teeth 11, 12, and 13. Clinically, she presented a thick phenotype with gingival recession type, RT1, with detectable cemento-enamel junction (A‒) in the second quadrant. To reduce the need of harvesting soft tissue grafts, the amount of cutting of muscles and vessels from the inner portion of the flap and mitigate the postoperative discomfort associated with the CAF, a novel surgical approach is described here using an advanced flap that incorporates an external incision along the mucogingival junction. RESULTS: The average root coverage achieved with the novel procedure presented in this case report was 95%, along with an increased amount of keratinized gingiva and minimal postoperative patient's discomfort. CONCLUSIONS: The mucosal released CAF is a promising technique in which the CAF technique alone may not be an indication. KEY POINTS: This technique has the following advantages: Reduce the need of harvesting soft tissue grafts. Reduce the amount of cutting of muscles and vessels from the inner portion of the flap. Minimal postoperative discomfort for the patient.

Polynucleotides and Hyaluronic Acid (PN-HA) Mixture With or Without Deproteinized Bovine Bone Mineral as a Novel Approach for the Treatment of Deep Infra-Bony Defects: A Retrospective Case-Series.

Polynucleotides and Hyaluronic Acid (PN-HA) mixture showed several effects in modulation of healing process. The aim of this study was to assess the safety and clinical performance of PN-HA alone or in association with Deproteinized Bovine Bone Mineral (DBBM) with papillary preservation flaps (PPF) in the treatment of residual pockets. A total of 43 patients with 55 infra-bony defects were recruited; 30% were smokers. The mean baseline Probing Depth (PD) was 7.7 ±1.9 mm with a corresponding mean recession (Rec) of 1.9± 1.3 mm. The depth of infra-bony defect at the surgical measurement was 5.2±2.1 mm. DBBM was applied at 56% of the defects considered as not-containing based on clinical judgment. Healing was uneventful at all sites. After one year, PD reduction was 4.4±1.8 mm with a Rec increase of 1.0 ±0.8 mm. Detected bone fill at x-ray was 3.5 ± 1.9mm. The multilevel analysis showed that absence of smoking habits was associated with improved PD reduction (P =0.026) and bone gain (P= 0.039). PN-HA mixture is a safe product for periodontal surgery and seems to promote clinical benefit in the treatment of residual pockets associated to infra-bony defects.

Molecular Analysis of Peri-implant Soft Tissue Response to Different Abutment Materials in Humans. A Pilot Study.

PURPOSE: To evaluate the response of human peri-implant soft tissue (PIST) on different healing abutment materials 24 hours after positioning, by assessing the expression of genes related to the early connective tissue wound healing response. MATERIALS AND METHODS: Experimental abutments of 4 different materials (A): grade 4 titanium, (B) grade 5 titanium, (C) zirconia and (D) PEEK, were mounted on installed implants in 5 patients, four different abutments each. Before implant placement, a gingival biopsy (control-CT) was obtained using a 2 mm diameter punch (T0). After 24 hours (T24), PIST biopsies were collected using a specifically designed custom-made cutting device. Real-time PCR was performed to analyze the expression of the following genes: COL-I, COL-III, MMP-1, TIMP-1,TGF-b1, FN, ITGA4, ITGA5, ITGB1, RAC-1, COL-IV, aSMA, IL-6 and CXCL-1. RESULTS: Gene expression analysis showed some differences between CT and abutment of different materials, although no significant differences were detected comparing the experimental groups. COL-I was significantly down-regulated in groups A and C compared to CT. MMP-1 and TIMP-1 increased in all the experimental groups, although at a lower extent in group A. FN, RAC-1, COL-IV and aSMA were down-regulated, especially in group A, in which CXCL-1 and IL-6 showed the lowest expression. CONCLUSIONS: The results of grade 4 titanium and zirconia abutments seem to be promising, since a lower expression of genes related with inflammation, myofibroblasts activation and ECM remodeling was observed when compared with grade 5 titanium and PEEK, without triggering a pro-fibrotic response in the early phases of PIST repair.

A comparative morphometric analysis of biodegradable scaffolds as carriers for dental pulp and periosteal stem cells in a model of bone regeneration.

Bone regeneration and bone fixation strategies in dentistry utilize scaffolds containing regenerating-competent cells as a replacement of the missing bone portions and gradually replaced by autologous tissues. Mesenchymal stem cells represent an ideal cell population for scaffold-based tissue engineering. Among them, dental pulp stem cells (DPSCs) and periosteal stem cells (PeSCs) have the potential to differentiate into a variety of cell types including osteocytes, suggesting that they can be used with this purpose. However, data on bone regeneration properties of these types of cells in scaffold-based tissue engineering are yet insufficient.In this study, we evaluated temporal dynamic bone regeneration (measured as a percentage of bone volume on the total area of the defect) induced by DPSCs or PeSCs when seeded with different scaffolds to fill critical calvarial defects in SCID Beige nude mice. Two commercially available scaffolds (granular deproteinized bovine bone with 10% porcine collagen and granular ß;-tricalcium phosphate) and one not yet introduced on the market (a sponge of agarose and nanohydroxyapatite) were used. The results showed that tissue-engineered constructs did not significantly improve bone-induced regeneration process when compared with the effect of scaffolds alone. In addition, the data also showed that the regeneration induced by ß;-tricalcium phosphate alone was higher after 8 weeks than that of scaffold seeded with the 2 stem cell lines. Altogether these findings suggest that further studies are needed to evaluate the potential of DPSCs and PeSCs in tissue construct and identify the appropriate conditions to generate bone tissue in critical-size defects.