Marcelo Diniz Carvalho

Effect of autologous bone marrow-derived cells associated with guided bone regeneration or not in the treatment of peri-implant defects

This study investigated the effect of bone marrow-derived cells associated with guided bone regeneration in the treatment of dehiscence bone defects around dental implants. Iliac-derived bone marrow cells were harvested from dogs and phenotypically characterized with regard to their osteogenic properties. After teeth extraction, three implant sites were drilled, dehiscences created and implants placed. Dehiscences were randomly assigned to: bone marrow-derived cells, bone marrow-derived cells+guided bone regeneration, and control (no treatment). After 3 months, implants with adjacent tissues were processed histologically, bone-to-implant contact, bone fill within the threads, new bone area in a zone lateral to the implant, new bone height, and new bone weight at the bottom of the defect were determined. Phenotypic characterization demonstrated that bone marrow-derived cells presented osteogenic potential. Statistically higher bone fill within the threads was observed in both bone marrow-derived cells+guided bone regeneration bone marrow-derived cell groups compared with the control group (P<0.05), with no difference between the groups treated with cells (P>0.05). For the other parameters (new bone area, bone-to-implant contact, new bone height and new bone weight), only the bone marrow-derived cells+guided bone regeneration group presented higher values compared with the non-treated control (P<0.05). Bone marrow-derived cells provided promising results for peri-implantar bone regeneration, although the combined approach seems to be relevant, especially to bone formation out of the implant threads.

Autologous periodontal ligament cells in the treatment of class II furcation defects: a study in dogs: Use of PDL cells for tissue engineering

AIM The goal of this study was to histologically investigate the use of periodontal ligament cells (PDL cells) in tissue engineering to regenerate class II furcation defects. MATERIAL AND METHODS PDL cells were obtained from the mandibular tooth extracted from each dog (seven), cultured in vitro and phenotypically characterized with regard to their biological properties. Following, bilateral class II furcation lesions were created at maxillary 3rd premolars and were randomly assigned to the test group [PDL cells+guided tissue regeneration (GTR)] or the control group (GTR). After 3 months, the animals were euthanized to evaluate the histometric parameters. RESULTS In vitro, PDL cells were able to promote mineral nodule formation and to express bone sialoprotein, type I collagen and alkaline phosphatase. Histometrically, data analysis demonstrated that the cell-treated group presented a superior length of new cementum (6.00 ± 1.50 and 8.08 ± 1.08 mm), a greater extension of periodontal regeneration (3.94 ± 1.20 and 7.28 ± 1.00 mm), a lower formation of connective tissue/epithelium (2.15 ± 1.92 and 0.60 ± 0.99 mm), a larger area of new bone (7.01 ± 0.61 and 9.02 ± 2.30 mm(2)) and a smaller area of connective tissue/epithelium (5.90 ± 1.67 and 4.22 ± 0.95 mm(2)), when compared with control group. CONCLUSION PDL cells in association with GTR may significantly promote periodontal regeneration in class II furcation defects in dog.

Platelet-rich plasma plus bioactive glass in the treatment of intra-bony defects: a study in dogs

Objective This study was designed to evaluate, histomorphometrically, the association of platelet-rich plasma (PRP) and bioactive glass (BG) in the treatment of periodontal intrabony defects. Material and Methods Nine mongrel dogs were included in the study. Three-wall intrabony defects were surgically created at the mesial and distal aspect of first mandibular molar and exposed to plaque accumulation for 1 month. The defects were randomly assigned to the groups: control, BG, PRP, PRP+BG. Dogs were sacrificed 90 days after the surgeries. The histometric parameters evaluated were: length of sulcular and junctional epithelium, connective tissue adaptation, new cementum, new bone, defect extension and area of new bone filling the defect. Results A superior area of new bone was observed in PRP+BG and BG (13.80±2.32 mm2 and 15.63±2.64 mm2, respectively) when compared to the other groups (8.19±1.46 mm2 and 8.81±1.47 mm2 for control and PRP, respectively). No statistically significant differences were observed in the remaining parameters. Conclusion Within the limits of this study, it may be concluded that PRP failed to provide statistically significant improvements in the histometric parameters.

Platelet-rich plasma in the treatment of Class II furcation defects: a histometrical study in dogs

Objective This study was designed to evaluate the potential adjunctive benefits of platelet-rich plasma (PRP) when used with guided-tissue regeneration (GTR) and bioactive glass (BG) in the treatment of Class II furcation lesions. Material and Methods Bilateral Class II furcation lesions were surgically created and allowed to become chronic in the mandibular third premolars of 9 dogs. The defects were randomly assigned to: A) GTR+BG and B) GTR+BG+PRP. Similar defects were created in the maxillary third premolars and received the same treatments after 45 days. Dogs were sacrificed 90 days after the first treatment. The histometric parameters evaluated were: connective tissue adaptation, new cementum, new bone, mineralized bone area, non-mineralized bone area, and residual BG particle area. Results Data analysis showed a superior length of new cementum and a greater mineralized bone area for group B in both periods (p<0.05). The non-mineralized bone area was greater in the control group (p<0.05) in both periods. Conclusion Within the limits of this study, it can be concluded that the use of PRP in the treatment of Class II furcation defects may enhance the amount of new cementum and provide a more mineralized bone in a shorter period of time.

Peri‐implant reconstruction using autologous periosteum‐derived cells and guided bone regeneration

AIM This investigation evaluated the bone healing in peri-implant defects treated with periosteum-derived cells (PCs) and guided bone regeneration (GBR). MATERIAL AND METHODS PCs were harvested from six beagle dogs and characterized in vitro with regard to their osteogenic properties. The animals were subjected to teeth extraction in the mandible, and after 3 months of healing, implant sites were drilled, bone dehiscences were created and implants were placed. Dehiscences were randomly assigned to: PCs+GBR, GBR, PCs and non-treated defects. After 3 months, the implants/adjacent tissues were processed. Bone-to-implant contact (BIC) bone fill (BF) within implant threads, and bone area (BA) in a zone lateral to the implant were obtained. RESULTS In vitro analyses confirmed the osteogenic potential of PCs. Histometrically, no statistically significant differences were observed among the PCs+GBR, GBR and PCs groups for both BF and BIC (p>0.05), whereas these groups showed statistically higher values, as compared with the non-treated group (p<0.05). With respect to BA, the PCs+GBR and GBR groups presented significantly higher means, as compared with the PCs and non-treated groups (p<0.05). CONCLUSION Although successful outcomes have been promoted by using the combined approach, PCs in conjunction with membranes did not provide additional benefit during peri-implant bone regeneration, when compared with the therapeutic approaches used alone.

Healing Patterns After Subgingival Placement of a Resin-Modified Glass-Ionomer Restoration: A Histometric Study in Dogs

The aim of this study was to evaluate, clinically and histometrically, the effects of subgingival placement of a resin-modified glass-ionomer restoration during flap surgery. Nine dogs were included in this study. The mandibular canines were randomly assigned to receive either a transgingival resin-modified glass-ionomer restoration (test group) or no restoration (control group). The apical margins of the restorations in the test group and a reference notch on those in the control group were placed at the level of the bone crest. Clinical parameters were recorded 7 days before sacrifice. The dogs were sacrificed after 107 days, and undecalcified sections were obtained for histologic evaluation. Clinically, both groups presented significant clinical attachment loss and an increase in probing depth, but differences between groups were not statistically significant (P > .05). Histologically, a significant difference between groups was observed for length of epithelium (test, 4.05 ± 0.57 mm; control, 3.36 ± 0.63 mm; P = .01). The test group showed more bone resorption (2.02 ± 1.47 mm) when compared with the control group (0.74 ± 0.37 mm) (P = .048). It can be concluded that even with the claimed favorable properties of resin-modified glass ionomer, the presence of the restoration within the biologic width causes increased migration of the apical epithelium and bone resorption.