Cell Therapy Based on Gingiva-Derived Mesenchymal Stem Cells Seeded in a Xenogeneic Collagen Matrix for Root Coverage of RT1 Gingival Lesions: An In Vivo Experimental Study.

(1) Background: To investigate the effect of a xenogeneic collagen matrix (CMX) seeded with autologous gingiva-derived mesenchymal cells (GMSCs) when combined with a coronally advanced flap (CAF) in the treatment of localized gingival recession type 1 (RT1). (2) Methods: Dehiscence-type defects were created in seven dogs. GMSCs were isolated, transfected with a vector carrying green fluorescent protein (GFP) and expanded. Once chronified, the defects were randomly treated with (1) CAF plus the combination of CMX and GFP+ GMSCs, (2) CAF plus CMX with autologous fibroblasts, (3) CAF plus CMX and (4) CAF alone. Histological and clinical outcomes at 2- and 6-week healing periods were analyzed and compared among groups. (3) Results: Histologically, the addition of autologous cells to the CMX resulted in reduced inflammation and a variable degree of new cementum/bone formation. CMX plus GMSCs resulted in greater mean recession reduction (1.42; SD = 1.88 mm) and percentage of teeth with recession reduction of ≥2 mm (57%) when compared to the other groups, although these differences were not statistically significant. (4) Conclusions: The histometric and clinical results indicated a positive trend favouring the combination of CMX and GMSCs with the CAF when compared to the groups without cells, although these differences were not statistically significant.

Immunohistochemical characteristics of lateral bone augmentation using different biomaterials around chronic peri-implant dehiscence defects: An experimental in vivo study.

AIM: To investigate the immunohistochemical characteristics of a highly porous synthetic bone substitute and a cross-linked collagen membrane for guided bone regeneration. METHODS: Three experimental groups were randomly allocated at chronic peri-implant dehiscence defect in 8 beagle dogs: (i) biphasic calcium phosphate covered by a cross-linked collagen membrane (test group), (ii) deproteinized bovine bone mineral covered by a natural collagen membrane (positive control) and (iii) no treatment (negative control). After 8 and 16 weeks of submerged healing, dissected tissue blocks were processed for immunohistochemical analysis. Seven antibodies were used to detect the remaining osteogenic and angiogenic potential, and quantitative immunohistochemical analysis was done by software. RESULTS: The antigen reactivity of alkaline phosphatase was significantly higher in the test group compared to the positive and negative controls, and it maintained till 16 weeks. The intensity of osteocalcin was significantly higher in the positive control at 8 weeks than the other groups, but significantly decreased at 16 weeks and no difference was found between the groups. A significant large number of TRAP-positive cells were observed in the test group mainly around the remaining particles at 16 weeks. The angiogenic potential was comparable between the groups showing no difference in the expression of transglutaminase II and vascular endothelial growth factor. CONCLUSION: Guided bone regeneration combining a highly porous biphasic calcium phosphate synthetic biomaterial with a crosslinked collagen membrane, resulted in extended osteogenic potential when compared to the combination of deproteinized bovine bone mineral and a native collagen membrane.

Periodontal regeneration using a xenogeneic bone substitute seeded with autologous periodontal ligament-derived mesenchymal stem cells: A 12-month quasi-randomized controlled pilot clinical trial.

AIM: To evaluate the safety and efficacy of autologous periodontal ligament-derived mesenchymal stem cells (PDL-MSCs) embedded in a xenogeneic bone substitute (XBS) for the regenerative treatment of intra-bony periodontal defects. MATERIAL AND METHODS: This quasi-randomized controlled pilot phase II clinical trial included patients requiring a tooth extraction and presence of one intra-bony lesion (1-2 walls). Patients were allocated to either the experimental (XBS + 10 × 106 PDL-MSCs/100 mg) or the control group (XBS). Clinical and radiographical parameters were recorded at baseline, 6, 9 and 12 months. The presence of adverse events was also evaluated. Chi-square, Student's t test, Mann-Whitney U, repeated-measures ANOVA and regression models were used. RESULTS: Twenty patients were included. No serious adverse events were reported. Patients in the experimental group (n = 9) showed greater clinical attachment level (CAL) gain (1.44, standard deviation [SD] = 1.87) and probing pocket depth (PPD) reduction (2.33, SD = 1.32) than the control group (n = 10; CAL gain = 0.88, SD = 1.68, and PPD reduction = 2.10, SD = 2.46), without statistically significant differences. CONCLUSION: The application of PDL-MSCs to XBS for the treatment of one- to two-wall intra-bony lesions was safe and resulted in low postoperative morbidity and appropriate healing, although its additional benefit, when compared with the XBS alone, was not demonstrated.

Prevalence and risk indicators of gingival recessions in an Italian school of dentistry and dental hygiene: a cross-sectional study.

OBJECTIVES: The aim of this cross-sectional study is to (i) determine the prevalence, extent, severity, and distribution of gingival recessions and patient perception in a young population and (ii) to identify potential risk indicators. MATERIAL AND METHODS: Two hundred fifty-one students with a mean age of 22.9 ± 4.7, attending the School of Dentistry and Dental Hygiene of Vita-Salute San Raffaele University (Milan, Italy) were included. The subjects had undergone a clinical evaluation, by two calibrated examiner, and a questionnaire. Demographic and clinical data were collected to evaluate association of these factors with gingival recessions. RESULTS: The prevalence of gingival recessions at patient and tooth level was 39% and 5.2%, respectively. The only factor associated with the presence of GR was age. On the other hand, age and smoking were associated with the extent, whereas BOP, NCCLs and KT were associated with the severity. Out of 98 subjects presenting at least one GR, 63 (64%) were conscious of the presence of the GR. NCCLs were also strongly associated with the perception of the recession by the patient. CONCLUSIONS: There is a low prevalence of buccal gingival recessions in this sample of Italian students. More than 50% of the sample was aware of the problem. Almost all patients presenting symptomatology or aesthetic concern requested appropriate therapy. CLINICAL RELEVANCE: The findings highlight the low relevance of gingival recessions in daily practice and the importance of controlling potential risk indicators in young populations.

Prevalence and risk indicators of peri-implantitis in a sample of university-based dental patients in Italy: A cross-sectional study.

AIM: Reports regarding prevalence of peri-implant diseases show widely varying prevalence rates, which can be explained partially by variable diagnostic criteria adopted. Furthermore, several different factors have been associated with peri-implant diseases. Hence, the aim of this cross-sectional study is to (a) determine the prevalence, extent and severity of peri-implant diseases in patients enrolled in a university dental clinic and (b) to evaluate the association between peri-implantitis and patient/implant-related factors. MATERIAL AND METHODS: A total of 237 subjects from the Dental Department of Vita-Salute San Raffaele University (Milan, Italy) with 831 implants with more than 1 year of follow-up after loading were clinically evaluated. Implants showing bleeding on probing (BOP), with or without suppuration, and/or probing pocket depth (PPD) ≥ 4 mm, were radiographically analysed. Demographic and clinical data were collected to evaluate by multilevel regression analysis association with peri-implantitis. RESULTS: The prevalence of peri-implant mucositis and peri-implantitis was 38.8% and 35%, respectively. Patients with a FMBS > 25%, having ≥4 implants as well as implants with plaque, PPD ≥ 4 mm or less than 1 mm of keratinized mucosa presented higher odds ratios for peri-implantitis. CONCLUSIONS: Peri-implant diseases are frequent conditions affecting >70% of the patients. Several patient/implant-related factors may influence the risk for peri-implantitis.

Outcomes After 25 Years of Periodontal Treatment and Maintenance of a Patient Affected by Generalized Severe Aggressive Periodontitis.

This report describes the long-term outcomes of nonsurgical periodontal therapy and supportive periodontal treatment (SPT) of a 21-year-old patient affected by generalized aggressive periodontitis at multiple teeth with a compromised prognosis. After 25 years of SPT, no teeth had been extracted and no periodontal pockets associated with bleeding on probing were present. Radiographic analysis showed an improvement in infrabony defects, demonstrating long-term improvement is possible with nonsurgical periodontal treatment provided that smoking is not present and the patient is included in a strict SPT.

Soft tissue wound healing at teeth, dental implants and the edentulous ridge when using barrier membranes, growth and differentiation factors and soft tissue substitutes.

AIM: To review the biological processes of wound healing following periodontal and periimplant plastic surgery when different technologies are used in a) the coverage of root and implant dehiscences, b) the augmentation of keratinized tissue (KT) and c) the augmentation of soft tissue volume. MATERIALS & METHODS: An electronic search from The National Library of Medicine (MEDLINE-PubMed) was performed: English articles with research focus in oral soft tissue regeneration, providing histological outcomes, either from animal experimental studies or human biopsy material were included. RESULTS: Barrier membranes, enamel matrix derivatives, growth factors, allogeneic and xenogeneic soft tissue substitutes have been used in soft tissue regeneration demonstrating different degrees of regeneration. In root coverage, these technologies were able to improve new attachment, although none has shown complete regeneration. In KT augmentation, tissue-engineered allogenic products and xenogeneic collagen matrixes demonstrated integration within the host connective tissue and promotion of keratinization. In soft tissue augmentation and peri-implant plastic surgery there are no histological data currently available. CONCLUSIONS: Soft tissue substitutes, growth differentiation factors demonstrated promising histological results in terms of soft tissue regeneration and keratinization, whereas there is a need for further studies to prove their added value in soft tissue augmentation.

Surgical protocols for ridge preservation after tooth extraction. A systematic review.

OBJECTIVE: This systematic review aims to evaluate the scientific evidence on the efficacy in the surgical protocols designed for preserving the alveolar ridge after tooth extraction and to evaluate how these techniques affect the placement of dental implants and the final implant supported restoration. MATERIAL AND METHODS: A thorough search in MEDLINE-PubMed, Embase and the Cochrane Central Register of controlled trials (CENTRAL) was conducted up to February 2011. Randomized clinical trials and prospective cohort studies with a follow-up of at least 3 months reporting changes on both the hard and soft tissues (height and/or width) of the alveolar process (mm or %) after tooth extraction were considered for inclusion. RESULTS: The screening of titles and abstracts resulted in 14 publications meeting the eligibility criteria. Data from nine of these 14 studies could be grouped in the meta-analyses. Results from the meta-analyses showed a statistically significant greater ridge reduction in bone height for control groups as compared to test groups (weighted mean differences, WMD = -1.47 mm; 95% CI [-1.982, -0.953]; P < 0.001; heterogeneity: I(2) = 13.1%; χ(2) P-value = 0.314) and a significant greater reduction in bone width for control groups compared to the test groups (WMD = -1.830 mm; 95% CI [-2.947, -0.732]; P = 0.001; heterogeneity: I(2) = 0%; χ(2) P-value = 0.837). Subgroup analysis was based on the surgical protocol used for the socket preservation (flapless/flapped, barrier membrane/no membrane, primary intention healing/no primary healing) and on the measurement method utilized to evaluate morphological changes. Meta-regression analyses demonstrated a statistically significant difference favoring the flapped subgroup in terms of bone width (meta-regression; slope = 2.26; 95% IC [1.01; 3.51]; P = 0.003). CONCLUSIONS: The potential benefit of socket preservation therapies was demonstrated resulting in significantly less vertical and horizontal contraction of the alveolar bone crest. The scientific evidence does not provide clear guidelines in regards to the type of biomaterial, or surgical procedure, although a significant positive effect of the flapped surgery was observed. There are no data available to draw conclusions on the consequences of such benefits on the long-term outcomes of implant therapy.

17beta-estradiol promotes cementoblast proliferation and cementum formation in experimental periodontitis.

BACKGROUND: Periodontitis is a chronic inflammatory condition that leads to the destruction of the tooth-supporting tissues. Its treatment includes the arrest of the inflammatory process and, in some circumstances, the restoration of the lost anatomy and function, including the formation of new cementum, periodontal ligament (PDL), and bone. With this goal, we investigated the effects of low concentrations of 17beta-estradiol on human cementoblast proliferation and its possible regenerative potential in vivo. METHODS: Human cementum-derived cells obtained from a healthy human premolar were isolated and characterized by immunocytochemistry. Cell proliferation assays were performed to test the effects of 100 nM 17beta-estradiol and enamel matrix derivative (EMD). Three-wall intrabony periodontal defects were created in beagle dogs. After 1 month of plaque accumulation, 0.225 mg 17beta-estradiol impregnated in a collagen sponge was applied to randomly selected defects (test group), whereas a collagen sponge impregnated in a culture medium was applied to the control group. After 3 months, specimens were obtained, and tissue regeneration was assessed by histometric analysis. RESULTS: Cells spreading out from human tooth-layer explants were able to form cell colonies, produce a mineral matrix, and express osteocalcin, indicating they were cementoblast-like cells. In contrast, PDL fibroblasts did not express osteocalcin. 17beta-estradiol, but not EMD, increased the rate of human cementoblast cell proliferation in vitro by 2.5-fold. Histometric results from the treated periodontal defects revealed that 17beta-estradiol promoted the formation of 2.94 mm of new cementum, (45% of the defects) compared to 1.54 mm of new cementum in the control group (28% of the defects). Furthermore, the test group showed an inhibition of epithelial downgrowth and a gain of new connective tissue attachment. CONCLUSION: 17beta-estradiol promoted human cementoblast cell proliferation in vitro and periodontal regeneration in an experimental periodontitis model.