Jaime Lozada

Platelet-rich plasma application in sinus graft surgery: Part I--Background and processing techniques.

The uses of cytokine growth factors in soft tissue applications has been reported on. The scientific background and various processing techniques to prepare the autologous materials are reviewed here. An ongoing research project to study grafting of the maxillary sinus for bone regeneration and implant site preparation with the growth factor Platelet Rich Plasma is outlined.

Bone Formation in the Maxillary Sinus by Using Platelet-rich Plasma: An Experimental Study in Sheep

Recently, platelet-rich plasma (PRP) has been proven to be an effective regeneration adjunct when combined with autogenous bone in the reconstruction of mandibular defects. However, little is known about the effect of PRP when combined with a bone allograft in the maxillary sinus. The purpose of this study was to quantitatively evaluate the ability of PRP to enhance bone regeneration in the maxillary sinus of sheep when combined with demineralized freeze-dried bone allograft (DFDBA) and cortical cancellous freeze-dried bone allograft (CCFDBA). Ten sheep were selected for bilateral sinus augmentation DFDBA + CCFDBA + PRP (test) and DFDBA + CCFDBA (control). Five were sacrificed at 3 months and the other 5 at 6 months. Hematology tests were performed for platelet count, and histology slides were obtained for histomorphometric analysis taking 2 measures of interest: total area (square millimeters) and percentage of bone fill. Student t tests showed no significant difference between test and control groups for total area (P > .25) and percentage of bone fill (P > .80) at either 3 or 6 months. The control group showed no statistical difference for total area (P < .095) and percentage of bone fill (P <.60) between 3- and 6-month healing times. The test group, however, showed a significant increase in total area (P <.025) but not in percentage of bone fill (P <.40) for the 2 healing periods. When the treatments were compared for interactions within the animal model, no clear tendency was evident for the test group to perform in relation to the control group regarding total area (r = .766, P < .01). A moderate tendency existed between the percentages of bone filled (r = .824, P < .005). Platelet-rich plasma showed higher platelet count than did the whole blood (2 to 5 times). However, no correlation was found between the log ratio and the bone measures. Within the limitations of this study, PRP failed to enhance or accelerate bone regeneration in the maxillary sinus of sheep when combined with bone allograft.

Use of titanium mesh for staged localized alveolar ridge augmentation: clinical and histologic-histomorphometric evaluation.

The use of titanium mesh for localized alveolar ridge augmentation was evaluated by clinical, radiographic, laboratory, and histologic-histomorphometric evaluation. Seventeen patients participated in this study. All patients required localized alveolar ridge augmentation before placement of dental implants. An equal mixture of autogenous bone graft and inorganic bovine mineral (Bio-Oss) was used as a bone graft material. Autogenous bone graft was harvested intraorally. Titanium mesh was submerged for 8.47 months (SD 2.83). Impressions were taken intraorally before bone grafting, 6 months after bone grafting, and 6 months after implant placement. Impressions were used to measure the volume of alveolar ridge augmentation and provide linear laboratory measurements regarding the results of bone augmentation. Bone quality (type II-IV) was recorded during implant surgery. Standardized linear tomographs were taken before bone grafting and before implant placement. A biopsy was harvested with a trephine bur from the grafted area during implant surgery for histologic-histomorphometric evaluation. In all cases the grafted area had adequate bone volume and consistency for placement of dental implants. Early mesh exposure (2 weeks) was observed in 2 patients, and late exposure (>3 months) was observed in 4 patients. Volumetric laboratory measurements indicated 0.86 cc (SD 0.69) alveolar augmentation 1 month after bone grafting, 0.73 cc (SD 0.60) 6 months after bone grafting, and 0.71 cc (SD 0.57) 6 months after implant placement. This indicated 15.11% resorption 6 months after bone grafting, and no further resorption occurred after implant placement. Linear laboratory measurements indicated vertical augmentation of 2.94 mm (SD 0.86) 1 month after bone grafting, 2.59 mm (SD 0.91) 6 months after bone grafting, and 2.65 mm (SD 1.14) 6 months after implant placement. The corresponding measurements for labial-buccal augmentation were 4.47 mm (SD 1.55), 3.88 mm (SD 1.43), and 3.82 mm (SD 1.47). Radiographic evaluation indicated 2.56 mm (SD 1.32) vertical augmentation and 3.75 mm (SD 1.33) labial-buccal augmentation. Histomorphometric evaluation indicated 36.47% (SD 10.05) new bone formation, 49.18% (SD 6.92) connective tissue, and 14.35% (SD 5.85) residual Bio-Oss particles; 44.65% (SD 22.58) of the Bio-Oss surface was in tight contact with newly formed bone. The use of titanium mesh for localized alveolar ridge augmentation with a mixture of autogenous intraorally harvested bone graft and Bio-Oss offered adequate bone volume for placement of dental implants. Intraorally harvested autogenous bone graft mixed with Bio-Oss under a titanium mesh offered 36.47% new bone formation, and 15.11% resorption occurred 6 months after bone grafting.

Clinical, Histologic, and Histomorphometric Evaluation of Mineralized Solvent-dehydrated Bone Allograft (Puros) in Human Maxillary Sinus Grafts

Demineralized freeze-dried bone allografts (DFDBA) have been successfully used alone or in composite grafts for many decades. Little research has been done on the effect of retaining the mineral content of bone allografts. This study histologically and histomorphometrically evaluated a new mineralized bone allograft material placed in human atrophic maxillary sinuses. Seven partially edentulous patients requiring sinus grafts before implant placement were selected for this study Their age range was 56 to 81 years (mean 67.7 years). Test grafts consisted of a mineralized solvent-dehydrated cancellous bone allograft, and control grafts were a composite of DFDBA and deproteinized bovine bone xenograft (1:1). Bilateral cases (n = 3) received both test and control grafts on opposite sides, and unilateral cases received either a test (n = 3) or control (n = 1) graft only. At 10 months, core biopsies were taken from each graft site, and dental implants were placed into the augmented bone. All bone grafts resulted in new bone formation and all implants osseointegrated. Test grafts resorbed and were replaced by newly formed bone significantly faster and in greater quantities than were control grafts. No complications with grafts or implants were noted. Both test and control grafts achieved excellent results. The faster bone formation observed with the test graft may be due, in part, to its smaller particle size compared with the bovine portion of the control graft. Test grafts were either replaced by new bone or displayed new bone-to-particle surface contact in higher percentages than did control grafts. No differences in osseointegration or graft stability were noted 2 years after the study.

Effects of Sealing the Perforated Sinus Membrane with a Resorbable Collagen Membrane: A Pilot Study in Humans

The effects of repairing the perforated sinus membrane with collagen membrane are unknown. The purpose of this pilot study was to clinically, histologically, and histomorphometrically evaluate the results of repairing the perforated sinus membrane with resorbable collagen membrane. A split-mouth design was followed in the current study. Five subjects requiring bilateral sinus grafting were included in the study, where one site was accidentally perforated during sinus augmentation procedures and the other site was not perforated. The perforated sites were repaired with a resorbable collagen membrane. Dental implants were placed at a second stage and biopsies were harvested from both sinuses. New bone formation was measured for all sites. Implant survival was recorded at second-stage surgery. Nonperforated sites demonstrated significantly more bone formation (34.40%) than perforated sites (12.80%) (P = .016). Implant survival at second-stage surgery was significantly inferior in perforated sites (54.5%) when compared with nonperforated sites (100%) (P = .0146). The study demonstrated that perforation and repair of the Schneiderian membrane can compromise new bone formation and implant survival rate.

Immediate Single Tooth Replacement With Subepithelial Connective Tissue Graft Using Platform Switching Implants: A Case Series

This case series evaluated the facial gingival stability following single immediate tooth replacement in conjunction with subepithelial connective tissue graft (SCTG). Implant success rate and peri-implant tissue response were also reported. Ten patients (6 male, 4 female), with a mean age of 52.1 (range = 22.7 to 67.1) years, underwent immediate implant placement and provisionalization with SCTG and were evaluated clinically and radiographically at presurgery (T0), at the time of immediate tooth replacement and SCTG (T1), and 3 months (T2), 6 months (T3), and 12 months (T4) after surgery. Data were analyzed using the Friedman and Wilcoxon signed-ranks tests at the significance level of α = .05. At 1 year, 9 of 10 implants remained osseointegrated with the overall mean marginal bone change of -0.31 mm and a mean facial gingival level change of -0.05 mm. The modified plaque index scores showed that patients were able to maintain a good level of hygiene throughout the study. The papilla index score indicated that at T4, more than 50% of the papilla fill was observed in 89% of all sites. When proper 3-dimensional implant position is achieved and bone graft is placed into the implant-socket gap, favorable success rate and peri-implant tissue response of platform switching implants can be achieved following immediate tooth replacement in conjunction with subepithelial connective tissue graft.

Clinical, Radiographic, and Histologic Evaluation of Maxillary Bone Reconstruction by Using a Titanium Mesh and Autogenous Iliac Graft: A Case Report

The current clinical report describes the use of titanium mesh for maxillary alveolar ridge augmentation. Autogenous bone graft was harvested from the iliac crest and was loaded on a titanium mesh that was left in the patients maxilla for 7 months before it was removed. Twelve months after the bone grafting procedure the patient received 10 implants on the maxilla, and a biopsy was taken from the augmented ridge. CT scan examination was performed before and after the maxillary ridge augmentation. Clinical evaluation revealed successful integration of the graft. The radiographic analysis demonstrated that a 10-mm vertical ridge augmentation had been achieved. Histologic evaluation revealed remnants of the autogenous bone graft still present, whereas the grafted area had a reduced remodeling activity. The clinical report demonstrated the potential of the titanium mesh to achieve extensive alveolar ridge augmentation, whereas the augmented ridge may possess an inferior capability forbone remodeling.

Simultaneous vertical guided bone regeneration and guided tissue regeneration in the posterior maxilla using recombinant human platelet-derived growth factor: a case report.

This clinical case report describes and demonstrates successful use of recombinant human platelet-derived growth factor (rhPDGF-BB) in conjunction with autogenous bone, anorganic bone mineral, and barrier membranes to reconstruct severe alveolar bone defects. A combined sinus augmentation and vertical alveolar ridge augmentation was successfully performed. In addition, a significant amount of periodontal bone gain was achieved in close apposition to a previously denuded root surface, which is significant from a periodontal standpoint, given the possibility of vertical periodontal regeneration.

Digitally planned and fabricated mandibular fixed complete dentures. Part 2. Prosthodontic phase.

Part 1 of this patient report described a prosthetically driven protocol that used computer-aided engineering for the fabrication of a mandibular conversion denture and maxillary provisional complete denture using the AvaDent Digital Denture system. The report demonstrated that this system combined with NobelClinician implant-planning software can be used to efficiently convert a digital denture into an immediately loaded provisional implant-supported fixed complete denture (hybrid prosthesis). Part 2 of the patient report describes the technique and steps involved in the fabrication of a digitally planned and fabricated mandibular fixed complete denture with incorporated titanium milled bar opposed by a definitive computer-aided design/computer-assisted manufacture-milled maxillary complete denture.

Use of a Digitally Planned and Fabricated Mandibular Complete Denture for Easy Conversion to an Immediately Loaded Provisional Fixed Complete Denture. Part 1. Planning and Surgical Phase

This article describes a unique prosthetically driven protocol that uses computeraided engineering to develop sophisticated, scientific algorithms that guide the fabrication of a conversion denture using the AvaDent Digital Denture system (Global Dental Science). This system is combined with Nobel Clinician (Nobel Biocare) implant-planning software to optimize accuracy and to make it easier and faster to convert a denture to an immediately loaded provisional implant supported fixed complete denture following implant placement, using a NobelGuide surgical template.