Peri-implant Parameters of Dental Implants Inserted in Prefabricated Microvascular Fibular Flaps: A Retrospective Study.

PURPOSE: To assess the peri-implant and flap parameters of the prefabricated microvascular fibula flap and determine the dental implant survival rate. MATERIALS AND METHODS: This retrospective study investigated a cohort of subjects who received prefabricated microvascular fibula flaps at two highly specialized tumor reconstruction centers. The subjects had all suffered atrophy or a large segmental defect of the jaws due to tumor resection or injury. Two independent surgeons determined the dental implant survival rate and assessed the peri-implant parameters and flap parameters during clinical follow-up. RESULTS: In total, 41 subjects were treated with a prefabricated fibula flap between 1999 and 2012. Of these, 17 subjects (10 male, 7 female) with a total of 62 dental implants were examined. The other 24 subjects were unavailable for assessment and had to be excluded. Ten of the 62 dental implants (16.1%) had to be removed due to peri-implantitis before the follow-up assessment. Follow-up assessments were performed at intervals ranging from 2 to 12 years (mean: 7.2 years) after fibula flap transplantation. The dental implant survival rate was found to be 83.9%. A total of 208 dental surfaces were assessed. Overall, 96% of all surfaces had a pocket depth (PD) of ≤ 4 mm and 4% had a pocket depth of > 5 mm. An attachment level (AL) of 3 mm was measured in 48.5% of implants and ≥ 5 mm was measured in 15.9% of implants. Dental implants with a PD > 4 mm showed a significantly higher plaque index (PI) (75%; P = .0057), papillary bleeding index (PBI) (62.5%; P = .0094), and radiologic bone loss (P = .0014) compared to dental implants with a PD ≤ 4 mm. CONCLUSIONS: Reconstructive surgery using microvascular fibula flaps represents an alternative tool for oral rehabilitation in subjects suffering from a large segmental defect in the maxillary or mandibular bone compared to the conventional method. However, it appears that the different ossification processes that develop the fibula and the jawbones affect dental implant survival.

Peri-implant Parameters of Dental Implants Inserted in Prefabricated Microvascular Fibular Flaps: A Retrospective Study.

PURPOSE: To assess the peri-implant and flap parameters of the prefabricated microvascular fibula flap and determine the dental implant survival rate. MATERIALS AND METHODS: This retrospective study investigated a cohort of subjects who received prefabricated microvascular fibula flaps at two highly specialized tumor reconstruction centers. The subjects had all suffered atrophy or a large segmental defect of the jaws due to tumor resection or injury. Two independent surgeons determined the dental implant survival rate and assessed the peri-implant parameters and flap parameters during clinical follow-up. RESULTS: In total, 41 subjects were treated with a prefabricated fibula flap between 1999 and 2012. Of these, 17 subjects (10 male, 7 female) with a total of 62 dental implants were examined. The other 24 subjects were unavailable for assessment and had to be excluded. Ten of the 62 dental implants (16.1%) had to be removed due to peri-implantitis before the follow-up assessment. Follow-up assessments were performed at intervals ranging from 2 to 12 years (mean: 7.2 years) after fibula flap transplantation. The dental implant survival rate was found to be 83.9%. A total of 208 dental surfaces were assessed. Overall, 96% of all surfaces had a pocket depth (PD) of ≤ 4 mm and 4% had a pocket depth of > 5 mm. An attachment level (AL) of 3 mm was measured in 48.5% of implants and ≥ 5 mm was measured in 15.9% of implants. Dental implants with a PD > 4 mm showed a significantly higher plaque index (PI) (75%; P = .0057), papillary bleeding index (PBI) (62.5%; P = .0094), and radiologic bone loss (P = .0014) compared to dental implants with a PD ≤ 4 mm. CONCLUSIONS: Reconstructive surgery using microvascular fibula flaps represents an alternative tool for oral rehabilitation in subjects suffering from a large segmental defect in the maxillary or mandibular bone compared to the conventional method. However, it appears that the different ossification processes that develop the fibula and the jawbones affect dental implant survival.

Accuracy of virtually planned and conventionally placed implants in edentulous cadaver maxillae and mandibles: a preliminary report.

STATEMENT OF PROBLEM: The accuracy of mental navigation is thought to depend on the clinician's spatial ability. Mental navigation, therefore, is associated with deviations between the mental plan and the definitive implant position. To learn more about the deviation that might occur, it is important to evaluate the accuracy of mental navigation during placement of implants. PURPOSE: The purpose of the study was to compare accuracy outcomes between virtually planned and conventionally placed implants, and among surgeons with varying experience. MATERIAL AND METHODS: Five completely edentulous sets of maxillae and mandibles from human cadaver heads were scanned by computed tomography. Five surgeons planned and placed 60 implants into these jaws, and accuracy was analyzed for 4 parameters: coronal and apical positions, angulation, and depth. The preoperative and postoperative computed tomographies were aligned in voxel-based registration software, which allowed comparison between virtually planned implant positions and actual implant positions. Data were analyzed with the t test (α=.05), ANOVA, and the Scheffé test. RESULTS: Mean (standard deviation) values were as follows: apex, 2.33 ±1.20 mm (range, 0.51-6.31 mm); coronal, 1.88 ±1.02 mm (range, 0.2-5.0 mm); angle, 7.34 ±3.62 degrees (range, 0.19-16.57 degrees); and depth, 0.03 ±1.15 mm (range, -3.47 to 2.10 mm). The apex and coronal position and the angle differed significantly between the virtually planned and actually placed implants. Significant between-surgeon differences were found in implant depth and coronal position. The apex and coronal positions differed significantly between the upper and lower jaw, with better performance achieved in the upper jaw. CONCLUSIONS: The results found statistically significant differences between the virtually planned and conventionally placed implants and among the 5 surgeons.

Clinical and radiological evaluation of a template-guided (NobelGuide™) treatment concept.

OBJECTIVES: The study was designed to evaluate the clinical use of the NobelGuide(™) concept over a follow-up period of 12 months with respect to implant success and survival rates, development of soft tissue condition and recording of potential surgical and prosthetic complications. In addition, radiological assessment of peri-implant bone levels was performed at the 1-year follow-up post-implant placement. MATERIAL AND METHODS: Thirty patients (male/female = 15/15) with partially dentate and edentulous mandibles and maxillae were included. All patients were planned and operated on using the computer-aided, template-guided treatment concept NobelGuide(™). Overall, 163 implants (NobelReplace(®) Tapered Groovy) were placed (mandible/maxilla = 107/56 implants). Recall appointments were performed after 1-2 weeks, 1, 3, 6 and 12 months after implant placement. Clinical parameters of the soft tissue conditions [e.g. bleeding on probing (BoP), pocket probing depth ≥3 mm (PPD), marginal plaque index (mPI)] and the dentist's esthetic and functional evaluation using a visual analogue scale (VAS) were documented. Marginal bone level was evaluated on radiographs made at implant insertion and at the 1-year follow-up. RESULTS: All 30 patients with 161 implants completed the 1-year follow-up resulting in a cumulative survival rate of 98.8% (two implant losses). Clinical parameters improved in a majority of the implants. The mean marginal bone level at implant insertion and at 1-year follow-up was reported with 0.17 mm (SD 1.24; n = 125) and -1.39 mm (SD 1.27; n = 110), respectively. The mean change in bone level from implant insertion to 1 year was -1.44 mm (SD 1.35; n = 98). CONCLUSIONS: The 1-year follow-up showed a cumulative survival rate and success rate of 98.8% and 96.3%, respectively. Immediate or delayed loading of implants using a flapless, guided surgery approach (NobelGuide(™)) appears to be a viable concept demonstrating good clinical and radiographic outcomes at the 1-year time point.

Early loading of hydrophilic titanium implants inserted in low-mineralized (D3 and D4) bone: one year results of a prospective clinical trial.

INTRODUCTION: Pure titanium is the material of choice for contemporary dental implants. However, superficial reaction of the moderately rough titanium surface with atmospheric components decreases its hydrophilicity. INICELL® represents a chemical alteration and hydrophilization of a moderately rough i. e. sand-blasted and acid-etched titanium surface. The hydrophilicity leads to a more homogenous adsorption of proteins on the implant surface in-vitro, supporting the activation of a higher number of platelets and the generation of a homogenous, complete fibrin matrix in the early phases of osseointegration. This in turn helps to reduce the healing time and enhances the predictability of osseointegration in compromised bony situations.The objective of this case series trial was therefore to investigate if early loading (after 8 weeks) of hydrophilic INICELL implants is feasible in patients with reduced bone quality. METHODS: In 10 patients, 35 hydrophilic implants were placed in sites revealing bone quality class 3 and 4, and uncovered after 4 weeks. Eight weeks later implants were released for loading if the tactile resistance was ≥35 Ncm. Lower resistances resulted in 12 weeks initial healing period. Insertion torque, ISQ, tactile resistance and vertical bone level were evaluated at implant installation, after 4 weeks (uncovering), 8 or 12 weeks (loading), and 12 weeks and one year after loading. RESULTS: Mean implant insertion torque was 21 Ncm. 31 (88.6%) showed a tactile resistance of >35 Ncm after eight weeks and were released for prosthetic loading. Eight weeks after insertion, one implant (2.9%) had to be removed following a soft tissue complication. One implant had to be removed after 4 weeks due to a technical complication (fractured Osstell-abutment), it was therefore excluded from the analysis.33 of 34 implants (97%) were loaded to occlusion and were in situ/functional one year after implantation. ISQs increased from 43 at baseline to 63 at eight weeks, and 72 at three months after loading. Then, ISQ remained constant until one year after loading. CONCLUSIONS: Within the limitations of this prospective case series, hydrophilic implants may allow for shortening of the initial healing period even in bone with compromised density.

Prefabricated fibular flaps for reconstruction of defects of the maxillofacial skeleton: planning, technique, and long-term experience.

Reconstruction of complex defects involving the maxilla or mandible often requires transfer of free vascularized tissue. In the conventional approach, a flap is transferred to provide vital tissue, and subsequent shaping and debulking are required. The authors present their experience with prefabrication of vascularized fibular flaps. Since 1999, 48 prefabricated flaps have been used to reconstruct 28 maxillary and 20 mandibular defects. The technique involves two surgical steps (prefabrication and flap transfer) and requires accurate planning, done with a solid model of the skull. Correct positioning of the prefabricated flap is accomplished by using the occlusion as a guide. Planning includes fabrication of a provisional prosthesis that is fixed to the flap with implants. Putting the prosthesis into occlusion determines the position of the flap.

Importance of patient-specific intraoperative guides in complex maxillofacial reconstruction.

BACKGROUND: Conventional maxillofacial reconstruction often leads to suboptimal results due to inaccurate planning or surgical difficulties in adjusting a free flap and osteosynthesis plates into a three-dimensional defect. OBJECTIVES: To justify the importance of patient-specific intraoperative guides in complex maxillofacial reconstruction. CLINICAL EXAMPLE: A 40-year old patient underwent a left hemimaxillectomy for an adenoid cystic carcinoma of the palate. Six years later, massive recurrence required radical resection of the left orbit and reconstruction with cranial bone grafts and a free latissimus dorsi flap. Postoperative radiotherapy resulted in local osteoradionecrosis. Surgical revision and restoration of the maxillary defect with a prefabricated fibula flap was performed. The authors provide ample information on the application of computer-aided design and manufacturing (CAD-CAM) and rapid prototyping at each reconstructive step. DISCUSSION: Stereolithographic models enable simulation of the resective and reconstructive phases, prebending of reconstruction plates and fabrication of surgical guides. CONCLUSIONS: Optimal restitution of complex maxillofacial defects requires meticulous planning of the surgical and prosthetic phases and effective transfer of the plan to the operating room through patient specific guides. CAD-CAM technology and stereolithographic models represent an effective strategy to achieve this. Improved patient outcomes and intraoperative efficiency certainly offset the inherent increase in costs.

In vitro biomechanical comparison of the effect of pattern, inclination, and size of positional screws on load resistance for bilateral sagittal split osteotomy.

PURPOSE: The purpose of this in vitro investigation was to determine whether the pattern, angle of placement, or size of positional screws affected their ability to resist vertical loads resembling mastication in the bilateral sagittal split osteotomy system. MATERIALS AND METHODS: Standardized bone substitutes were secured with three 12- to 16 mm-long, 1.85-, 2.0-, 2.1-, and 2.4-mm outer diameter, self-tapping titanium screws (Synthes, Solothurn, Switzerland) in various patterns using a positional screw technique. These patterns included transbuccal triangular, intraoral triangular, and transbuccal linear patterns. The models were secured in a jig and subjected to vertical loads by a mechanical testing unit (1475 UPM; Zwick, Ulm, Germany) until failure. Loading test data analysis was based on peak load values resulting in mechanical deformation of the system (1-, 3-, and 5-mm displacement), maximal force, and stiffness (load/displacement slope curve) for each group. Means and standard deviations were derived and compared for statistical significance using univariate analysis of variance with a confidence level of 95% (P values < .05). RESULTS: The designed study demonstrated that 1.85- and 2.0-mm-diameter positional screws provided similar stability in all 3 setups. Three screws placed in an inverted L pattern at 90° (simulating a transbuccal approach) showed significantly higher resistance to vertical forces for advancement movements at 1-, 3-, and 5-mm displacement when compared with the inverted L group of screws placed at an angle (intraoral approach) or 3 screws in a linear pattern placed at 90° (transbuccal approach) (P < .01). CONCLUSIONS: Under the conditions tested in this in vitro study, differences in the load resistance of positional screws placed in a transbuccal or intraoral approach could be demonstrated depending on the fixation technique. The transbuccal group of 3 screws in an inverted L pattern showed significantly greater stability than the intraoral group of 3 screws placed in an inverted L pattern and the transbuccal group of 3 screws in a linear pattern. Resistance to vertical loads with 1.85-mm screws was similar to that with the standard 2.0-mm screws in all 3 setups. The results of this study suggest that the angle of screw placement (surgical approach) and pattern have a greater influence on the stability of the bilateral sagittal split osteotomy system than the screw size.

[Zygoma implants--an option for the treatment of severe atrophy of the maxilla? Case report]. / Zygoma-Implantate. Therapiealternative in der stark atrophierten Maxilla? Ein Fallbericht.

The reconstruction of the severe atrophy of the maxilla using dental implants requires extensive surgical treatments. Sinus lift procedure, ridge augmentation with free bone grafts or free vascularized bone transfers represent the common techniques. With regard to a higher life expectancy the number of patients suffering from limited chewing function based on atrophic bone conditions will increase. In addition to a higher number of failed implants in elderly people ask for other treatment strategies to regain proper oral function with limited surgical effort. This case report presents the failed treatment of maxilla, using disc implants and shows the new maxillary reconstruction using Brånemark-Zygoma implants combined with standard Nobel Replace implants in order to avoid extensive augmentation procedure.

[The interdisciplinary fixed restoration of an edentulous maxilla with a pronounced resorption of the alveolar crest. A case report. Part I: The immediate reconstruction]. / Die interdisziplinäre festsitzende Rekonstruktion eines zahnlosen Oberkiefers mit ausgeprägter Resorption des Alveolarfortsatzes. Ein Fallbericht. Teil 1: Die Sofortversorgung.

Edentulous patients wearing a conventional complete denture often request a fixed restoration for functional, esthetical and/or psychosocial reasons. For these patients implant-supported fixed dental prostheses are a prosthetic means of choice. However, after years of edentulism often a marked resorption of the alveolar crest has taken place, asking for bone augmentation before implant placement. Thus, fixed implant reconstructions are time and cost intense and stressful for the patient. This case report documents the immediate fixed reconstruction in the edentulous maxilla after ridge augmentation with a cortical cancellous bone graft from the iliac crest and implant placement. A CAD/CAM-system was used for implant planning and the fabrication of a drilling guide. The prosthetic reconstruction was inserted immediately after implant placement.

[Navigated implant placement using a bone supported CT-guided surgical template. Case report]. / Die navigierte Implantation unter Verwendung einer knochengestützten Operationsschablone. Ein Fallbericht.

Surgical navigation allows precise implant placement and minimizes the risk of interferences with anatomical structures. Computerized implant planning based on tomographic data can be clinically realized by surgical templates. These are normally produced by stereo lithographic rapid prototyping. Accurate placement of virtually planned dental implants depends on a precise fabrication and positioning of the surgical template. Bone-, tooth-, implant-, and/or soft tissue-supported surgical templates allow for different micromovements. This report documents the diagnostics and surgical procedures of implant placement in an edentulous patient. Implant fixed complete dentures in the maxilla and mandible were planned. In the maxilla implants were inserted with the aid of a conventional surgical template. In the mandible a bone supported CT-guided surgical template was used.

[The prosthetic rehabilitation of a patient after gunshot wound and initial maxillofacial surgical reconstruction. A case report]. / Die defektprothetische Versorgung eines Patienten mit Status nach einer Schussverletzung und chirurgischer Rekonstruktion. Ein Fallbericht.

An improvement of prognosis after tumour therapy as well as a rather high number of multiple traumas in the craniofacial area imply a high treatment need for craniofacial tissue defects. For a successful rehabilitation of these individuals, reconstructive oral and maxillofacial surgery and prosthodontics must collaborate closely and synergistically. Besides medical and psychological findings, functional and esthetical aspects need to be taken into account. In this case report the prosthetic reconstruction of a patient with a tooth-supported telescopic defect prosthesis in the maxilla and with a multiple-unit implant-supported fixed prosthesis plus two full ceramic crowns in the mandible is shown. The prosthetic solution was indicated after maxillofacial reconstruction due to the consequence of a suicide attempt.

[Alveolar ridge atrophy. The free vascularized fibular flap as alternative treatment in severe alveolar atrophy]. / Kieferkammatrophie. Das präformierte vaskularisierte Fibulatransplantat als alternative Behandlungsmethode bei ausgeprägter Kieferkammatrophie.

Implant-supported overdentures are the goal of treatment of the edentulous atrophic jaw. To gain adequate height there is in some instances need for additional bone augmentation. Ridge augmentation using a free vascularised fibular flap is one of the newer techniques. Prefabrication of fibular flaps, as described in this article, is a two-stage procedure to overcome the problems of osseointegration and missing attached gingiva. Accurate pre-operative 3-D-model planning, implant placement and vestibuloplasty in the first stage allow for occlusion driven reconstruction and immediate function in the second stage after a delay of six weeks. Based on our clinical experience the technique and the results are discussed.

Endoscopic approaches to maxillary orthognathic surgery.

Endoscopically assisted surgery has become an essential component in many fields of surgical specialties. The implementation of this technique to craniofacial and maxillofacial surgery is a recent development. Endoscopic approach to subcondylar mandible fractures has been established as reliable surgical method.

Reconstruction of maxillary and mandibular defects using prefabricated microvascular fibular grafts and osseointegrated dental implants -- a prospective study.

The fibular flap can be used for a variety of indications. Recently, the treatment of four patients with severely atrophied upper jaws using a method to prefabricate the vascularized fibular graft has been published. This technique consists of a two-stage operation procedure that allows simultaneous prosthodontic rehabilitation and immediate placement of dental implants. In this paper eight patients with 29 ITI implants (Straumann AG, Waldenburg, Switzerland) who had reconstruction of either the upper or lower jaw are presented. The aim of the study was (i) to evaluate the behavior of the newly formed soft tissue around implants inserted in the fibula by applying periodontal parameters, (ii) to monitor prospectively the integration of the implants in the fibular graft, and (iii) to assess the osseous integration of the fibular graft used for reconstruction of the upper or lower jaw. Two implants failed during the observation time because of avascular bone at the distal end of the fibular graft. Stabilization of the graft, however, was never compromised. Due to the prefabrication firmly attached gingiva-like soft tissue could be provided preventing periimplant soft tissue inflammation and facilitating oral hygiene. After 1 year of observation the mean attachment level was similar to implants placed in original bone whereas vertical bone loss measured radiographically was lower in the present study. This may indicate that the remodeling of a bicortical bone requires a longer period of time compared with the bone of the alveolar crest. The prospective 1-year results are promising but long-term evaluation of periodontal and radiological parameters are required.

Analysis of 3D bone ingrowth into polymer scaffolds via micro-computed tomography imaging.

This paper illustrates the utility of micro-computed tomography (micro-CT) to study the process of tissue engineered bone growth. A micro-CT facility for imaging and visualising biomaterials in three dimensions (3D) is described. The facility is capable of acquiring 3D images made up of 2000(3) voxels on specimens up to 60mm in extent with resolutions down to 2 microm. This allows the 3D structure of tissue engineered materials to be imaged across three orders of magnitude of detail. The capabilities of micro-CT are demonstrated by imaging the Haversian network within human femoral cortical bone (distal diaphysis) and bone ingrowth into a porous scaffold at varying resolutions. Phase identification combined with 3D visualisation enables one to observe the complex topology of the canalicular system of the cortical bone. Imaging of the tissue engineered bone at a scale of 1cm and resolutions of 10 microm allows visualisation of the complex ingrowth of bone into the polymer scaffold. Further imaging at 2 microm resolution allows observation of bone ultra-structure. These observations illustrate the benefits of tomography over traditional techniques for the characterisation of bone morphology and interconnectivity and performs a complimentary role to current histomorphometric techniques.

Interface of unloaded titanium implants in the iliac crest, fibula, and scapula: a histomorphometric and biomechanical study in the pig.

PURPOSE: Prefabrication of free vascularized fibular flaps is a 2-stage procedure for the reconstruction of maxillary and mandibular defects. The delay between prefabrication and flap transfer is 6 weeks and depends on biomechanical stability and osseointegration of the implants. The purpose of this animal study was to evaluate implant stability by measuring the removal torque values (RTVs) at 3, 6, and 12 weeks and to compare the results with interface strength of the bone-implant surface in the fibula, the scapula, and the iliac crest under unloaded conditions. MATERIALS AND METHODS: ITI implants (n = 108) with a sandblasted and acid-etched surface were placed in the fibula, the scapula, and the iliac crest of 6 Yorkshire pigs. Biomechanical, histologic, and histomorphometric results were collected at 3, 6, and 12 weeks, respectively. RESULTS: Bicortical anchored 8-mm implants in the fibula (63.7 to 101.8 Ncm) showed RTVs similar to those of monocortical anchored 12-mm implants in the scapula (62.3 to 99.7 Ncm). The RTVs of monocortical anchored 8-mm and 10-mm implants in the iliac crest (19.1 to 44.3 Ncm) and the scapula (27.2 to 55.3 Ncm) were significantly lower. The bone-to-implant contact in the fibula at 3, 6, and 12 weeks (35.2%, 44.4%, and 46.8%, respectively) was similar to that in the iliac crest (24.2%, 44.2%, and 52.5%, respectively), but significantly lower than in the scapula (63.7%, 73.8%, and 74.2%, respectively). DISCUSSION AND CONCLUSION: Bicortical anchorage determined implant stability in the fibula, whereas interfacial strength seemed to define stability in the scapula. The quality and type of bone determined the bone's response in terms of biomechanical press fit or biologic interface strength.

Maxillofacial reconstruction with prefabricated osseous free flaps: a 3-year experience with 24 patients.

Between January of 1998 and May of 2002, 25 prefabricated osseous free flaps (23 fibula and two iliac crest flaps) were transferred in 24 patients to repair maxillary (six flaps) or mandibular (eight flaps) defects after tumor resection, severe maxillary (four flaps) or mandibular (one flap) atrophy (Cawood VI), maxillary (one flap) or mandibular (three flaps) defects after gunshot injury, and maxillary (two flaps) defects after traffic accidents. Prefabrication included insertion of dental implants, positioned with a drilling template in a preplanned position, and split-thickness grafting. Drilling template construction was based on the prosthetic planning. The template determined the position of the implants and the site and angulation of osteotomies, if necessary. The mean delay between prefabrication and flap transfer was 6 weeks (range, 4 to 8 weeks). While the flap was harvested, a bar construction with overdentures was mounted onto the implants. The overdentures were used as an occlusal key for exact three-dimensional positioning of the graft within the defect. The bar construction also helped to stabilize the horseshoe shape of the graft. The follow-up period ranged from 2 months to 4 years (mean, 21 months), during which time two total and three partial flap losses occurred. One total loss was due to thrombosis of the flap veins during the delay period, whereas the other total loss was caused by spasm of the peroneal artery. Two partial losses were due to oversegmentation of the flaps with necrosis of the distal fragment, whereas one partial loss was caused by disruption of the vessel from the distal part. Of the 90 implants that were inserted into the prefabricated flaps during the study period, 10 were lost in conjunction with flap failure; of the remaining 80 implants, four were lost during the observation period, for a success rate of 95 percent. Flap prefabrication based on prosthetic planning offers a powerful tool for various reconstructive problems in the maxillofacial area. Although it involves a two-stage procedure, the time for complete rehabilitation is shorter than with conventional procedures.

In vivo efficacy of bone-marrow-coated polycaprolactone scaffolds for the reconstruction of orbital defects in the pig.

Alloplastic materials offer a number of advantages over bone autografts in the reconstruction of craniofacial defects. These include: lack of donor site morbidity, unlimited quantities of available material, and the possibility to conform exactly to the defect. An ideal bioresorbable material would degrade slowly, and have osteoconductive properties to allow replacement and remodeling by osseous tissue. This is seldom observed, the materials instead being replaced by fibrous tissue. Polycaprolactone (PCL), an FDA-approved bioresorbable polymer, has several properties that might make it suitable for reconstruction of craniofacial defects. The technique of fused deposition modeling (FDM) allows for the fabrication of highly reproducible bioresorbable 3D scaffolds. The nature of the fully interconnected pore network might enhance vascular ingrowth and osteoconductive properties. It was hypothesized that coating the scaffolds in bone marrow might enhance bone formation due to the osteoinductive nature of the bone-marrow mesenchymal cells. This study aimed to test these hypotheses in the pig model. Defects measuring 2 x 2 cm were surgically created in each orbit of eight Yorkshire pigs. The orbits were divided into three groups: Group 1 (n=4), no reconstruction (control); Group 2 (n=6), reconstruction with no coated PCL scaffolds; and Group 3 (n=6) reconstruction with bone-marrow-coated PCL scaffolds. The results were evaluated at 3 months by histological and histomorphometric analyses. The defects in Group 1 were covered with fibrous scar tissue. The shape of the reconstructed area was insufficient. The defects in Groups 2 and 3 were reconstructed correctly. In Group 2 the noncoated scaffolds showed 4.5% of new bone formation compared with 14.1% in Group 3, which is statistically significant (p<0.05). The entirely interconnected 3D polycaprolactone scaffold seems to be a promising material. It induces the bone ingrowth required for reconstructing craniofacial and orbital defects. Further long-term evaluations of these PCL scaffolds must be made in order to confirm these conclusions.