Giuseppe Corinaldesi

Effect of Mesenchymal Stem Cells and Platelet-Rich Plasma on the Healing of Standardized Bone Defects in the Alveolar Ridge: A Comparative Histomorphometric Study in Minipigs

PURPOSE The purpose of this study was to test the effect of the combination of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) incorporated into a fluorohydroxyapatite (FHA) scaffold on bone regeneration in cylindrical defects in the edentulous mandibular ridge of minipigs. MATERIALS AND METHODS Two mandibular premolar teeth were extracted bilaterally in 8 adult minipigs. After 2 months, 4 standardized defects of 3.5 mm diameter and 8 mm depth were created in each root site. The defects were randomly grafted with autogenous mandibular bone, FHA alone, PRP-FHA, or MSCs-PRP-FHA. A resorbable collagen membrane was placed over the defect area and the flaps were sutured. The animals were sacrificed 3 months later and biopsy samples were taken from the defect sites for histologic and histomorphometric assessment. RESULTS There was no evidence of inflammation or adverse tissue reaction with either treatment. MSCs-PRP-FHA-treated sites showed new vital bone between residual grafting particles. PRP-FHA- and FHA-treated sites showed residual particles in a background of marrow soft tissue with a moderate quantity of newly formed bone. Autogenous bone (46.97%) and MSCs-PRP-FHA (45.28%) produced a significantly higher amount of vital bone than PRP-FHA (37.95%), or FHA alone (36.03%). Further, the MSCs-PRP-FHA-treated defects showed a significantly higher percentage of contact between graft particles and newly formed bone compared with PRP-FHA and FHA group (59.23% vs 48.37% and 46.43%, respectively). CONCLUSIONS Our results suggest that, in this animal model, the addition of MSCs to PRP-FHA enhances bone formation after 3 months.

Dose-dependent effect of adipose-derived adult stem cells on vertical bone regeneration in rabbit calvarium.

Previous in vivo studies have shown a limited potential for vertical bone regeneration using osteoconductive scaffolds alone. In the present study, we investigated whether the association of adipose-derived adult stem cells (ASCs) with anorganic bovine bone (ABB) scaffold improved bone formation and implant osseointegration in a vertical guided bone regeneration model. Two pre-formed titanium domes were placed on the calvaria of 12 rabbits. Four treatment modalities were evenly distributed among the 24 domes: ABB alone, and ABB containing 3 x 10(5), 3 x 10(6), or 3 x 10(7) cells/graft. After 1 month, the domes were removed and one titanium implant was placed into each augmented site. One month after the second operation, the animals were killed and biopsy specimens were examined by histomorphometric and micro-CT analyses. Results indicated that at all concentrations, the ASC-loaded groups showed significantly more new bone formation and higher mean values of bone-implant contact and bone density inside threads than the ABB group. Furthermore, ASCs demonstrated a dose-response relationship, with the highest dose chosen inducing more robust bone regeneration. This study suggests that the delivery of ASCs on ABB might effectively increase vertical bone regeneration and implant osseointegration, versus ABB alone.

Mesenchymal stem cells and platelet-rich plasma enhance bone formation in sinus grafting: a histomorphometric study in minipigs

OBJECTIVES Autologous, allogenic, and alloplastic materials for sinus augmentation have specific drawbacks, which has stimulated an ongoing search for new materials and tissue-engineering constructs. We investigated whether mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) seeded on a fluorohydroxyapatite (FH) scaffold can improve bone formation and bone-to-implant contact (BIC) in maxillary sinus grafting. MATERIAL AND METHODS Bilateral sinus augmentation procedures were performed in eight minipigs. MSCs, PRP, and FH scaffold (test site) or FH alone (control site) were grafted in each maxillary sinus. Distal to the osteotomy, one dental implant per sinus was placed in the grafting material through the facial sinus wall. The animals were killed 3 months after grafting, and block sections of the implant sites were harvested and prepared for histomorphometric analysis. RESULTS After 12 weeks, a significant increase in bone formation occurred in the test sites compared with the control sites (42.51%versus 18.98%; p=0.001). In addition, BIC was significantly greater in the test sites compared with the control sites in the regenerated area (23.71%versus 6.63%; p=0.028). CONCLUSIONS These findings show that sinus augmentation with MSCs-PRP, combined with FH may enhance bone formation and osseointegration of dental implants compared with FH alone in minipigs.

Mandibular third molar removal in young patients: an evaluation of 2 different flap designs.

PURPOSE To evaluate the influence of 2 different flap designs on periodontal healing and postoperative complications, after inferior third molar removal in young patients. PATIENTS AND METHODS Twenty-four mandibular third molars were extracted from 12 patients with an average age of 16 years. Patients were included in the study when radiographs at the time of surgery showed that only the crown of the germ was formed. Each patient underwent 2 extractions, using a triangular flap on one side and an envelope flap on the other. Periodontal probing was recorded at the preoperative visit, and 7 days, 3 months, and 6 months after extraction. Postoperative complications were recorded using a questionnaire completed by the patient for the week after the extraction. RESULTS The examination performed 7 days after the extraction demonstrated a deeper probing depth in all teeth examined. This increase was statistically greater (P < .05) for the first and second molars when an envelope flap was used. After 3 months, the probing depths returned to preoperative values. No significant differences were seen between the 2 flap designs when postoperative complications were considered. The average operating time was 30.66 minutes with the triangular flap, versus 35.66 minutes with the envelope flap. This difference was not significant. After 6 months, the 2 flap designs resulted in no difference in periodontal healing or complications, but 30% of the surgical extractions resulted in a debilitating postoperative period for the patients treated. CONCLUSIONS Although we observed statistically significant differences in probing depth between triangular and envelope flaps 7 days after the extraction of third molars with no root development, this was not important from a clinical perspective, because periodontal healing at 3 and 6 months was comparable. We believe that this is also the case with the extraction of third molars with fully formed roots. Another important finding was the presence of a debilitating postoperative period in most of the patients who underwent extraction, contrary to the beliefs of many surgeons.

Treatment of intrabony defects after impacted mandibular third molar removal with bioabsorbable and non-resorbable membranes.

BACKGROUND Mandibular second molar (M2) periodontal defects after third molar (M3) removal in high-risk patients are a clinical dilemma for clinicians. This study compares the healing of periodontal intrabony defects at distal surfaces of mandibular M2s using bioabsorbable and non-resorbable membranes. METHODS Eleven patients with bilateral probing depths (PDs) ≥6 mm distal to mandibular M2s and intrabony defects ≥3 mm, related to the total impaction of M3s, were treated with M3 extraction and covering of the surgical bone defect with a bioabsorbable collagen barrier on one side and a non-resorbable expanded polytetrafluoroethylene (ePTFE) barrier contralaterally. The PD, clinical attachment level (CAL), M2 mobility, and furcation class probing were evaluated preoperatively and 3, 6, and 9 months postoperatively. Intraoral periapical radiographs were taken immediately preoperatively and 3 and 9 months postoperatively. RESULTS Both treatment modalities were successful. At 9 months, the mean PD reduction was 5.2 ± 3.9 mm for bioabsorbable sites and 5.5 ± 3.0 mm for non-resorbable sites; the CAL gain was 5.9 ± 3.3 mm and 5.5 ± 3.4 mm, respectively. The outcome difference between the two sites for PD and CAL did not differ statistically (P >0.05) at any assessment time. CONCLUSION Bioabsorbable collagen membranes in guided tissue regeneration treatment of intrabony defects distal to the mandibular M2 obtained the same marked PD reductions and CAL gains as non-resorbable ePTFE membranes after M3 extraction.

Immediate functional loading of dental implants supporting a bar-retained maxillary overdenture: preliminary 12-month results.

BACKGROUND The present study evaluated the efficacy of a treatment consisting of placing and immediately loading implants with a bar-retained overdenture in edentulous maxillae. METHODS Twenty-two consecutive patients were treated with four or five implants rigidly connected with a bar, which were then loaded with a maxillary overdenture within 48 hours post-surgery. The patients were followed clinically and radiographically for 1 year after loading. The implant outcome with regard to survival and success was analyzed. Visual analog scale questionnaires were used to record patient function and satisfaction before and after implant treatment. RESULTS Of the 103 implants, three failed within 1 year. Two implants, although integrated, presented with marginal bone resorption (MBR) values higher than those proposed for successful implants. Cumulative survival and success rates of implants were 97.1% and 95.2%, respectively. The average MBR after 1 year was low (0.78 +/- 0.79 mm). The main prosthetic complication was the frequent need for complete relining of the prosthesis in the initial weeks after loading (27.2%). The questionnaire revealed a significant increase in all comfort, functional, and esthetic parameters (Friedman test; P <0.0001), except in the cleaning feasibility category; a significant decrease in satisfaction was observed in this category (Friedman test; P <0.05), indicating the difficulty patients had in maintaining a high level of oral hygiene. CONCLUSION These preliminary results suggest that immediate loading of multiple implants supporting a bar-retained overdenture may represent a predictable treatment option for the rehabilitation of the edentulous maxilla.

Implant prosthetic rehabilitation of posterior mandible after tumor ablation with inferior alveolar nerve mobilization and inlay bone grafting: a case report.

PURPOSE To report a successful clinical case of dental implant provisionalization of a posterior mandible resected for tumor ablation and subsequently reconstructed with interpositional bone grafting after mobilization of the inferior alveolar nerve. MATERIALS AND METHODS A 47-year-old woman with a severe posterior mandibular defect due to ablation of a squamous cell carcinoma was treated with transposition of the inferior alveolar nerve and inlay iliac bone graft. Four months later, 4 dental implants were inserted and immediately provisionalized. Bone core biopsies were taken during implant insertion. After an additional 3 months, a definitive fixed bridge was inserted. RESULTS At the 24-month follow-up visit, all implants appeared to have osseointegrated. The histologic examination showed that the grafted bone was lined by newly formed bone without gaps at the interface. CONCLUSIONS Inlay bone grafting can allow implant provisonalization of the posterior mandible even with a remarkable bone alveolar deficit after tumor ablation.

Short implants (6 mm) vs. vertical bone augmentation and standard-length implants (≥9 mm) in atrophic posterior mandibles: a 5-year retrospective study

This retrospective study compared the 5-year clinical and radiographic outcomes of short implants (6 mm) (short group), and standard-length implants (≥9mm) placed after a vertical augmentation with autologous bone blocks (augmentation group), supporting partial fixed prostheses in the posterior mandible. Forty-five partially edentulous patients were enrolled in the study and evaluated after 5 years: 22 (51 implants) in the augmentation group and 23 (46 implants) in the short group. Eight surgical complications occurred in the augmentation group versus none in the short group (P=0.003). One short implant failed before loading and one standard-length implant failed after 4 years because of peri-implantitis (P=1.0). Eight biological and two prosthetic complications occurred in the augmentation group vs. three biological and three prosthetic complications in the short group (P=0.09 and P=1.0, respectively). A mean marginal bone loss of 1.61±1.12mm in the augmentation group and 0.68±0.68mm in the short group was found (P=0.002). Within the limitations of this study, both techniques resulted in successful clinical results after 5 years, but short implants exhibited less surgical complications and marginal bone loss than standard-length implants placed in augmented bone.

CUSTOM-MADE TITANIUM MESH FOR MAXILLARY BONE AUGMENTATION WITH IMMEDIATE IMPLANTS AND DELAYED LOADING

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Successful resolution of juvenile paradental cysts after marsupialization in five consecutive patients

BACKGROUND Juvenile paradental cysts typically occur on the buccal aspect of mandibular first and second molars in children aged 6 to 11 years. The cysts may be treated by enucleation, with or without extraction of the involved teeth, or by marsupialization. This report demonstrates the success of a conservative surgical technique (marsupialization) and good outcomes in five juvenile paradental cyst cases. METHODS Five patients (two males, three females) with a mean age of 8.4 years, complaining of mandibular buccal swelling around the molars, underwent marsupialization of radiolucent lesions involving partially or fully erupted permanent first molars. Clinical, radiographic and histological characteristics led to diagnoses of juvenile paradental cysts. RESULTS The surgical procedures were simple to perform and resulted in complete remission of the lesions with no complications. The mean follow-up time was 2.8 years. No recurrences were observed, the related teeth developed normally, and complete periodontal healing was achieved. CONCLUSIONS The surgical marsupialization of juvenile paradental cysts achieved good outcomes without compromising the development of related teeth, and thus may be considered an appropriate treatment for paediatric patients.