Maxillary Bone Defect Reconstruction Using Porous Polyethylene Implants

Purpose: The aim of this study was to evaluate the bone repair process in the maxillary sinus in monkeys treated with high-density porous polyethylene (Medpor)Methods: Four capuchin monkeys (Cebus apella) were submitted to bilateral horizontal osteotomies in the anterior wall of the maxillary sinus and divided into 2 groups: control group, left side with no implants, and porous polyethylene group, right side with Medpor. After a period of 145 days after implant placement, the maxillae were removed for histologic and histometric analyses.Results: Bone repair in osteotomized areas took place by connective tissue in 58.5% and 58.7% in the control group and the porous polyethylene group, respectively. In the contact surface with Medpor, bone repair occurred in 41.3%.Conclusions: Medpor was not reabsorbed within the period of this study and allowed bone repair surrounding it. The porous polyethylene constitutes a feasible alternative for bone defect reconstruction.

Accuracy of zoomed digital image in the detection of periodontal bone defect: in vitro study

Objectives: (1) To evaluate the intraobserver agreement related to image interpretation and (2) to compare the accuracy of 100%, 200% and 400% zoomed digital images in the detection of simulated periodontal bone defects.Methods: Periodontal bone defects were created in 60 pig hemi-mandibles with slow-speed burs 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm and 3.0 mm in diameter. 180 standardized digital radiographs were made using Schick sensor and evaluated at 100%, 200% and 400% zooming. The intraobserver agreement was estimated by Kappa statistic (kappa). For the evaluation of diagnostic accuracy receiver operating characteristic (ROC) analysis was performed followed by chi-square test to compare the areas under ROC curves according to each level of zooming.Results: For 100%, 200% and 400% zooming the intraobserver agreement was moderate (kappa = 0.48, kappa = 0.54 and kappa = 0.43, respectively) and there were similar performances in the discrimination capacity, with ROC areas of 0.8611 (95% CI: 0.7660-0.9562), 0.8600 (95% CI: 0.7659-0.9540), and 0.8368 (95% CI: 0.7346-0.9390), respectively, with no statistical significant differences (chi(2)-test; P = 0.8440).Conclusions: A moderate intraobserver agreement was observed in the classification of periodontal bone defects and the 100%, 200% and 400% zoomed digital images presented similar performances in the detection of periodontal bone defects.

Tibial segmental bone defect treated with bone plate and cage filled with either xenogeneic composite or autologous cortical bone graft

Tibia segmental defect healing in sheep were clinically, radiographically and histologically evaluated. Twelve young sheep aged four to five months were divided into two groups, G1 and G2. A 3.5 cm long segmental defect was created in the right tibial diaphysis with maintenance of the periosteum. The bone defects in both groups were stabilized with a bone plate combined with a titanium cage. In G1 the cage was filled with pieces of autologous cortical bone graft. In G2 it was filled with a composite biomaterial which consisted of inorganic bovine bone, demineralized bovine bone, a pool of bovine bone morphogenetic proteins bound to absorbable ultra-thin powdered hydroxyapatiteand bone-derived denaturized collagen. Except for one G1 animal, all of them showed normal limb function 60 days after surgery. Radiographic examination showed initial formation of periosteal callus in both groups at osteo-tomy sites, over the plate or cage 15 days postoperatively. At 60 and 90 days callus remodeling occurred. Histological and morphometric analysis at 90 days after surgery showed that the quantity of implanted materials in G1 and G2 were similar, and the quantity of new bone formation was less (p = 0.0048) and more immature in G1 than G2, occupying 51 +/- 3.46% and 62 +/- 6.26% of the cage space, respectively. These results suggest that the composite biomaterial tested was a good alternative to autologous cartical bone graft in this experimental ovine tibial defect. However, additional evaluation is warranted prior to its clinical usage.

Comparison of simulated periodontal bone defect depth measured in digital radiographs in dedicated and non-dedicated software systems

Objectives: To compare simulated periodontal bone defect depth measured in digital radiographs with dedicated and non-dedicated software systems and to compare the depth measurements from each program with the measurements in dry mandibles.Methods: Forty periodontal bone defects were created at the proximal area of the first premolar in dry pig mandibles. Measurements of the defects were performed with a periodontal probe in the dry mandible. Periapical digital radiographs of the defects were recorded using the Schick sensor in a standardized exposure setting. All images were read using a Schick dedicated software system (CDR DICOM for Windows v.3.5), and three commonly available non-dedicated software systems (Vix Win 2000 v.1.2; Adobe Photoshop 7.0 and Image Tool 3.0). The defects were measured three times in each image and a consensus was reached among three examiners using the four software systems. The difference between the radiographic measurements was analysed using analysis of variance (ANOVA) and by comparing the measurements from each software system with the dry mandibles measurements using Student's t-test.Results: the mean values of the bone defects measured in the radiographs were 5.07 rum, 5.06 rum, 5.01 mm and 5.11 mm for CDR Digital Image and Communication in Medicine (DICOM) for Windows, Vix Win, Adobe Photoshop, and Image Tool, respectively, and 6.67 mm for the dry mandible. The means of the measurements performed in the four software systems were not significantly different, ANOVA (P = 0.958). A significant underestimation of defect depth was obtained when we compared the mean depths from each software system with the dry mandible measurements (t-test; P congruent to 0.000).Conclusions: the periodontal bone defect measurements in dedicated and in three non-dedicated software systems were not significantly different, but they all underestimated the measurements when compared with the measurements obtained in the dry mandibles.

Prosthetic rehabilitation of a bone defect with a teeth-implant supported, removable partial denture

The use of teeth-implant, mucosa-supported removable dentures for rehabilitation of partially edentulous patients involves highly complex biomechanical aspects. This type of prosthesis associates 3 kinds of support that react differently to the functional and parafunctional forces developed in the oral cavity. Although the construction of removable partial dentures may seem paradoxical when osseointegrated implants are placed, in some cases, this option is an excellent alternative to solve difficulties related to the anatomic, biologic, psychomotor, and financial conditions of the patient. This article reports on a case in which a teeth-implant, mucosa-supported removable partial denture was the option of choice for a patient with financial and anatomic limitations, having a large structural loss of the residual alveolar ridge caused by trauma by a gunshot injury at the mandible. The 5-year follow-up did not reveal any type of biomechanical or functional problem. Copyright © 2006 by Lippincott Williams and Wilkins.

Comparison between polyurethanes containing castor oil (Soft Segment) and cancellous bone autograft in the treatment of segmental bone defect induced in rabbits

The aim of this study is to compare polyurethanes containing castor oil (soft segment) in granular form compared to cancellous bone autograft applied to a segmental bone defect. Norfolk adult female rabbits - approximately 13 months of age with a mean body weight of 4.5 kg - are used. In both radial diaphyses, 1 cm osteoperiosteal segmental defects are created. The defect in the left radius is filled with the castor-oil-based polyurethane, and the right one, filled with cancellous bone autograft, collected from the left proximal humerus. The rabbits are euthanazed at 15, 30, 60, and 120 days postsurgery (5 animals/ period), for histological analyses. By radiographic analyses, at these time points, the bone regeneration is more evident and accelerated in the bone defects treated with the cancellous bone autograft. At 120 days postsurgery, the segmental bone defects treated with the cancellous bone autograft are totally reconstituted and remodeled, while the bone defects treated with polyurethane polymer have bone formation of 79%. Histological study shows that the polyurethane acts as a space filler, minimizing the local production of fibrous tissue. No granule degradation, resorption or any inflammatory reaction is detected. Thus, it is possible to conclude that the castor-oil-plant-based polyurethane - in the granule presentation - is biocompatible and osteointegrated, but does not show the same bone regeneration capacity as the cancellous bone autograft. © 2007 SAGE Publications.

New LLLT protocol to speed up the bone healing process-histometric and immunohistochemical analysis in rat calvarial bone defect

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reconstruction of alveolar bone defect with autogenous bone particles and osseointegrated implants: histologic analysis and 10 years monitoring

Maintaining the volume of the alveolar process after extraction can be achieved by immediate implant placement and guided bone regeneration, with or without the use of biomaterials. The authors present a case report with a 10 years follow-up, rehabilitation using osseointegrated implants in the extraction area and maintenance of the volume of the alveolar process with autogenous cortical bone shavings.

Bone defect repair on the alveolar wall of the maxillary sinus using collagen membranes and temporal fascia: an experimental study in monkeys

Few studies has been done using guided bone regeneration in maxillary sinus defects. AIM: To assess the bone repair process in surgical defects on the alveolar wall of the monkey maxillary sinus, which communicates with the sinus cavity, by using collagen membranes: Gen-derm - Genius Baumer, Pro-tape - Proline and autologous temporal fascia. MATERIALS AND METHODS: In this prospective and experimental study, orosinusal communications were performed in four tufted capuchin monkeys (Cebus apella) and histologic analysis was carried out 180 days after. RESULTS: In the defects without a cover (control), bone proliferation predominated in two animals and fibrous connective tissue predominated in the other two. In defects repaired with a temporal fascia flap, fibrous connective tissue predominated in three animals and bone proliferation predominated in one. In the defects repaired with Gen-derm or Pro-tape collagen membranes there was complete bone proliferation in three animals and fibrous connective tissue in one. CONCLUSIONS: Surgical defect can be repaired with both bone tissue and fibrous connective tissue in all study groups; collagen membranes was more beneficial in the bone repair process than temporal fascia or absence of a barrier.

Large segmental radius and ulna defect treated by bone transportation with the Ilizarov technique

An 8-year-old male Boxer with a severely contaminated open fracture of the left radius and ulna fracture, produced by a helicopter propeller, was treated using bone transport by the Ilizarov method. Extensive diaphyseal bone loss and soft-tissue vascular damage were present. The radius and ulna were stabilised with an Ilizarov ring external fixator. The bone defect was partially shortened and restored by gradual transport of a bone segment created from proximal segments of the radius and ulna. The external fixator was removed 4fi months after the beginning of the latency period, due to instability caused by osteolysis around the wires. A cast was placed for 3 weeks. Although the bone transport had resulted in formation of approximately 4 cm of bone, the antebrachium showed approximately 50% shortening when compared to the contralateral limb. The infection was eradicated, and the dog was able to bear weight on the operated limb when walking.

Latex use as an occlusive membrane for guided bone regeneration

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alveolar osseous defect in rat for cell therapy. Preliminary report

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of alveolex on the bone defects repair stimulated by rhBMP-2: Histomorphometric study

OBJECTIVE: The aim of this study was to evaluate histomorphometrically the effect of alveolex (Propolis 10%) on the repair of bone cavities in the calvaria of rats. MATERIALS and METHODS: A 5 mm diameter bone defect was made in the calvaria of male Wistar rats using the drill-type trephine. The defects were filled with rhBMP-21Alveolex, rhBMP-2, Alveolex, or coagulum. Twenty-eight animals with seven subjects on each were sacrificed 30 days after surgery and samples were fixed and embedded in paraffin. Histological sections stained by HE (hematoxylin and eosin) were obtained from the calvaria bone defect and analyzed by a differential point-counting method. RESULTS: Group I and II, rhBMP-21Alveolex and rhBMP-2, respectively, presented higher levels of newly formed bone than other groups (P < 0.001). There were not significant differences between groups I and II (P > 0.05). In addition, there was not significant difference between groups III and IV, Control-Coagulum and Alveolex, respectively (P > 0.05). CONCLUSION: Alveolex has increased the bone repair in calvaria defects of rats when associated to rhBMP-2, however without significant differences for rhBMP-2 isolated group; Alveolex isolated group showed the lowest levels of newly formed bone with no significant differences to coagulum group (control). Microsc. Res. Tech. 75: 36-41, 2012. (C) 2011 Wiley Periodicals, Inc.

Influence of microgap location and configuration on the periimplant bone morphology in submerged implants. An experimental study in dogs

Objectives: The vertical location of the implant-abutment connection influences the periimplant bone morphology. It is unknown, however, whether different microgap configurations cause different bone reactions. Therefore, in this study the bone morphologies of two different implant systems were compared.Material and methods: Three months after tooth extraction in eight mongrel dogs, two grit-blasted screw implants with internal Morse taper connection (ANK group) were placed on one side whereas the contralateral side received two oxidized screw implants with external hex (TIU group). One implant on each side was placed level with the bone (equicrestal), the second implant was inserted 1.5mm below bone level (subcrestal). After 3 months the implants were uncovered. Three months after stage two surgery, histometrical evaluations were performed in order to assess the periimplant bone levels (PBL), the first bone-to-implant contact points (BICP), the width (HBD) and the steepness (SLO) of the bone defect.Results: All implants osseointegrated clinically and histologically. Bone overgrowth of the microgap was seen in ANK implants only. No significant differences between ANK and TIU could be detected in neither vertical position for PBL and BICP. However, a tendency in favor of ANK was visible when the implants were placed subcrestally. In the parameters HBD (ANK equicrestal -0.23mm; TIU equicrestal -0.51mm; ANK subcrestal +0.19mm; TIU subcrestal -0.57mm) and SLO (ANK equicrestal 35.36 degrees; TIU equicrestal 63.22 degrees; ANK subcrestal 20.40 degrees; TIU subcrestal 44.43 degrees) more pronounced and significant differences were noted.Conclusions: Within the limits of this study, it is concluded that different microgap designs cause different shapes and sizes of the periimplant ('dish-shaped') bone defect in submerged implants both in equicrestal and subcrestal positions.

Influence of Microgap Location and Configuration on Peri-implant Bone Morphology in Nonsubmerged Implants: An Experimental Study in Dogs

Purpose: It is unknown whether different micro gap configurations can cause different pen-implant bone reactions. Therefore, this study sought to compare the peri-implant bone morphologies of two implant systems with different implant-abutment connections. Materials and Methods: Three months after mandibular tooth extractions in six mongrel dogs, two oxidized screw implants with an external-hex connection were inserted (hexed group) on one side, whereas on the contralateral side two grit-blasted screw implants with an internal Morse-taper connection (Morse group) were placed. on each side, one implant was inserted level with the bone (equicrestal) and the second implant was inserted 1.5 mm below the bony crest (subcrestal). Healing abutments were inserted immediately after implant placement. Three months later, the peri-implant bone levels, the first bone-to-implant contact points, and the width and steepness of the peri-implant bone defects were evaluated histometrically. Results: All 24 implants osseointegrated clinically and histologically. No statistically significant differences between the hexed group and Morse group were detected for either the vertical position for peri-implant bone levels (Morse equicrestal -0.16 mm, hexed equicrestal -0.22 mm, Morse subcrestal 1.50 mm, hexed subcrestal 0.94 mm) or for the first bone-to-implant contact points (Morse equicrestal -2.08 mm, hexed equicrestal -0.98 mm, Morse subcrestal -1.26 mm, hexed subcrestal -0.76 mm). For the parameters width (Morse equicrestal -0.15 mm, hexed equicrestal -0.59 mm, Morse subcrestal 0.28 mm, hexed subcrestal -0.70 mm) and steepness (Morse equicrestal 25.27 degree, hexed equicrestal 57.21 degree, Morse subcrestal 15.35 degree, hexed subcrestal 37.97 degree) of the pen-implant defect, highly significant differences were noted between the Morse group and the hexed group. Conclusion: Within the limits of this experiment, it can be concluded that different microgap configurations influence the size and shape of the peri-implant bone defect in nonsubmerged implants placed both at the crest and subcrestally. INT J ORAL MAXILLOFAC IMPLANTS 2010;25:540-547