Objectives: The study aimed to evaluate bone formation in periodontal fenestration defects in rats, using bone marrow mesenchymal stem cells (MSCs) or bone marrow concentrate (BMC) with propylene glycol alginate (PGA) as a vehicle. Methods: Periodontal fenestration defects (2mm high x 4mm wide x 1mm deep) were created in the mandible of isogenic rats. The animals were allocated into six groups and further divided into three subgroups for euthanasia at 15, 30 or 60 days postoperatively (n=6 in each subgroup). The control group (C group) was the spontaneous healing group. The PGA group received 25 µl of PGA as vehicle. For the MSC group, stem cells were collected from the iliac crest of two isogenic rats, isolated with Ficoll and cultured in flasks and separated by flow cytometry to obtain a CD45-90+ cell population. In the MSC group, a pellet containing 1.2 x 106 cells was applied to each defect. In the MSC-PGA group, 25 µl of PGA was added to the same pellet. In the BMC groups (BMC and BMC-PGA), 1 mL of bone marrow from iliac crest was aspirated immediately before surgery and was centrifuged twice to remove red cells and poor platelet plasma, producing a concentrate of MSCs and platelets. The BMC and BMC-PGA groups received 25 µl of BMC, but in the latter it was mixed with 25 µl PGA. After euthanasia, mandibles were fixed and scanned by computer microtomography. Bone volume, density and trabecular number and thickness were analysed by SigmaPlot™. The normality of the data was checked and one-way ANOVA used with a significance level of 5%. Results: Bone volume was increased in all groups and at all-time points (p 0.05), except the PGA group which was lower (p 0.05). At 30 days, trabecular thicknesses for MSC and MSC-PGA were similar (p > 0.05) and both were higher than the other groups (p Conclusion: Overall, the stem cells in the proper vehicle resulted in faster and more extensive bone regeneration in periodontal fenestration in rats. MSC alone and BMC in the vehicle were also associated with better bone regeneration than spontaneous healing or vehicle alone.

Objectives: Guided bone regeneration by means of membranes and bone substitutes is one of the most documented approaches for restoring deficient alveolar ridges. Despite routine use of the techniques, it is not known to what extent these approaches can restore the tissue volume lost after tooth extraction. The aim of this study was to analyse the volume loss occurring after extraction and how much lost volume can be recovered by three different bone augmentation procedures. Methods: To create the alveolar ridge defects, the teeth were sectioned in a buccal–lingual direction at the furcation level, and the mesial roots of M1 and P4 and distal roots of P3, P2 and P1 (monoradicular) were individually extracted. Three vertical grooves of about 6mm in height and 6mm in depth (as far as the lingual cortical bone) were prepared in order to eliminate the buccal bone plate. After 12 weeks, the dogs were randomly assigned to one of three regenerative procedures: graft-only (B) in which the defect was filled with a particulate bone substitute (Bio-Oss Collagen); membrane only (M) in which the defect was covered with a bioabsorbable collagen membrane (Bio-Gide); and combination group (T) in which the defect was filled with a particulate bone substitute (Bio-Oss Collagen) and membrane was added. Conventional polyvinyl impressions were taken before extraction and defect creation at one time point (T1), before regenerative surgery (T2) and after 3 months of healing (T3). The cast models were optically scanned to obtain stereolithography (STL) files. Linear and volumetric measurements included volumetric analysis, distance between surfaces, and tissue thickness at three levels below the alveolar ridge on the buccal side of the regenerated site(at 1, 3 and 5mm). Results: A total of 18 casts were obtained at T1, with 18 at T2 and 9 at T3. No impressions were taken at the time of sacrifice to avoid disturbing early healing. The box-shaped defects were effective in creating horizontal and vertical ridge deformities (comparison T1–T2). None of the three regenerative approaches resulted in complete reconstitution of the alveolar ridge to baseline dimensions (comparison T1–T3), although volume gain in groups B and T was significantly better than in groupM (comparison T2–T3). Conclusion: The three regenerative approaches failed to rebuild the post-extraction loss in tissue volume.

based on the book chapter by Michael K. McGuire Summary There is an extensive body of evidence relating to soft tissue keratinization and the mucogingival junction (MGJ). This chapter provides an overview of the subject, and revisits the anatomy of the tooth periodontium. The protocol it describes is a randomized trial that targets patients with two non-adjacent sites of one to four tooth spans and less than 2mm of keratinized gingiva. The pre-surgical phases include screening and baseline observations, and the procedure involves comparing an apically positioned flap plus vestibuloplasty (benchmark treatment) with a new therapy. The protocol describes preferred techniques for probing and taking punch biopsies, and specifies dimensions of the wound bed. The authors recommend removing existing keratinized gingiva from the mucosal flaps so that results with the gingival graft are more discernible. They give specific instructions on the method of taking clinical photos. Post-surgical evaluations take place over 6 months, and include patient-reports of postoperative pain and discomfort at the treatment and harvest sites, with inflammatory assessment by a scoring system and measures of apicocoronal width. Other practical recommendations include the use of probes that are calibrated for studies and a 3-mm biopsy punch for revealing the MGJ, as well as allowing a learning curve for surgical techniques, possible pilot patient procedures, carrying out batch surgeries and pre-study power calculations, and consulting a biostatistician. Open full-text PDF (1.4 MB)