Titanium Fixation Research Articles

Susceptibility to biofilm formation on 3D-printed titanium fixation plates used in the mandible: a preliminary study

ABSTRACT Background: In the oral and maxillofacial surgery, fixation plates are commonly used for the stabilization of bone fragments. Additive manufacturing has enabled us to design and create personalized fixation devices that would ideally fit any given fracture. Aim: The aim of the present preliminary study was to assess the susceptibility of 3D-printed titanium fixation plates to biofilm formation. Methods: Plates were manufactured using selective laser melting (SLM) from Ti-6Al-4 V. Reference strains of Streptococcus mutans, Staphyloccocus epidermidis, Staphylococcus aureus, Lactobacillus rhamnosus, and Candida albicans, were tested to evaluate the material’s susceptibility to biofilm formation over 48 hours. Biofilm formations were quantified by a colorimetric method and colony-forming units (CFU) quantification. Scanning electron microscopy (SEM) visualized the structure of the biofilm. Results: Surface analysis revealed the average roughness of 102.75 nm and irregular topography of the tested plates. They were susceptible to biofilm formation by all tested strains. The average CFUs were as follows: S. mutans (11.91 x 107) > S.epidermidis (4.45 x 107) > S. aureus (2.3 x 107) > C.albicans (1.22 x 107) > L. rhamnosus (0.78 x 107). Conclusions: The present preliminary study showed that rough surfaces of additively manufactured titanium plates are susceptible to microbial adhesion. The research should be continued in order to compare additively manufactured plates with other commercially available osteotomy plates. Therefore, we suggest caution when using this type of material.

Stability of bioresorbable plates following reduction of mandibular body fracture: Three-dimensional analysis

PurposeThe recent development of bioresorbable bone plates and screws allows plates to be applied to the load-bearing regions of the mandible and to remain in place over time without the need for removal. We hypothesized that the stability of composite plates and screws forged from unsintered hydroxyapatite particles and poly-l-lactide (u-HA/PLLA) is comparable to that of standard titanium fixation systems for the reduction of fractures of load-bearing regions of the mandibular body. Materials and methods40 patients underwent open reduction and internal fixation of the fractured mandibular body with either a titanium or u-HA/PLLA bone plate. Cone-beam CT images were obtained immediately postoperatively and at 6-month follow-up, and were analyzed for positional changes of the affected mandible. ResultsThere were no significant differences in the postoperative positional changes of reference points between the titanium and u-HA/PLLA miniplates, except for that for the coronoid process (p-value = 0.03). Multivariate regression analysis revealed no significant differences in spatial changes between the immediate postoperative and 6-month follow-up images, after adjusting for age and sex. ConclusionThe stability of bioresorbable u-HA/PLLA miniplates and screws was comparable to that of titanium miniplates and screws immediately postoperatively and at 6-month follow-up, following surgical reduction of fractures of load-bearing regions of the mandibular body. Bioresorbable osteosynthesis can be considered a viable alternative to titanium osteosynthesis.

In Vitro Evaluation of Bacterial Adhesion and Bacterial Viability of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis on the Abutment Surface of Titanium and Zirconium Dental Implants.

Objective To evaluate the in vitro adherence and viability of 3 bacterial species Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277) on the surfaces of dental implants of titanium, zirconium, and their respective fixing screws. Methods Two analysis groups were formed: group 1 with 3 titanium pillars and group 2 with 3 zirconium pillars, each with their respective fixing screws. Each of these groups was included in tubes with bacterial cultures of Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277). These samples were incubated at 37°C under anaerobic conditions. Bacterial adherence was assessed by measurement of the change in colony-forming units (CFU), and bacterial viability was evaluated with the colorimetric test of 3-(4,5-dimethylthiazol-2)-2,5 diphenyl tetrazolium bromide (MTT). Results The bacterial adhesion in the titanium abutments was higher for Streptococcus mutans (190.90 CFU/mL), and the viability was greater in Porphyromonas gingivalis (73.22%). The zirconium abutment group showed the highest adherence with Streptococcus mutans (331.82 CFU/mL) and the highest bacterial viability with the S. sanguinis strain (38.42%). The titanium fixation screws showed the highest adhesion with S. sanguinis (132.5 CFU/mL) compared to the zirconium fixation screws where S. mutans had the highest adhesion (145.5 CFU/mL). The bacterial viability of S. mutans was greater both in the titanium fixation screws and in the zirconium fixation screws 78.04% and 57.38%, respectively. Conclusions Our results indicate that there is in vitro bacterial adherence and viability in both titanium abutments and zirconium abutments and fixation screws for both. Streptococcus mutans is the microorganism that shows the greatest adherence to the surfaces of both titanium and zirconium and the fixing screws of the latter. On the contrary, bacterial viability is greater on the titanium abutments with P. gingivalis than on the zirconium abutments with S. sanguinis. With respect to the fixation screws, in both cases, the viability of S. mutans was greater with respect to the other bacteria. In general, the titanium abutments showed less adherence but greater bacterial viability.

Comparison of Titanium and Bioresorbable Plates in "A" Shape Plate Properties-Finite Element Analysis.

(1) Background: The main disadvantage of rigid fracture fixation is remain material after healing period. Implementation of resorbable plates prevents issues resulting from left plates. The aim of this study is to compare the usage of bioresorbable and titanium “A” shape condyle plate in condylar fractures. (2) Methods: Thickness of 1.0 mm, height of 31 mm, and width of 19 mm polylactic acid (PLLA) and titanium “A” shape plate with 2.0 mm-wide connecting bar and 9 holes were tested with finite element analysis in high right condylar neck fracture. (3) Results: On bone surface the highest stress is on the anterior bridge around first hole (approx. 100 MPa). The highest stress on screws is located in the first screw around plate in the anterior bridge and is greater in titanium (150 MPa) than PLLA (114 MPa). (4) Conclusion: Pressure on bone in PLLA osteosynthesis is two times higher than in titanium fixation. On small areas where pressure on bone is too high it causes local bone degradation around the fracture and may delay the healing process or make it impossible. Fixation by PLLA is such flexible that bone edges slide and twist what may lead to degradation of callus.

Titanium Mesh Implant Exposure Due To Pressure Gradient Fluctuation

Titanium mesh implants (TMIs) are used for various purposes in craniotomy. Although delayed implant exposure and thinning of the overlying skin are well-known complications, the mechanism has not yet been elucidated. We reviewed our cases and propose a mechanism for TMI exposure. From 2009 to 2018, we treated 14 patients with delayed titanium implant exposure after craniotomy. The exposed titanium implant was a TMI in 4 patients, a titanium mesh plate in 6 patients, and a titanium fixation plate with holes in 4 patients. We reviewed the preoperative computed tomography (CT) scans and operative findings. The interval between craniotomy and implant exposure was 13 years (range, 5-27). Implant exposure occurred at the temporal region in 7 patients, frontal region in 6 patients, and parietal region in 1 patient. The skin ulcer size ranged from 0.25 to 10 cm2 (mean, 1.95). In the patients with TMI exposure, the dura was expanded, and no residual epidural space was identified on the CT scans; however, epidural dead space was revealed on the CT scan in the patients with titanium mesh plate or titanium fixation plate exposure. We believe that the key factor resulting in delayed titanium mesh exposure is the pressure gradient between the atmosphere and the intracranial space. Fluctuation of this gradient exerts dynamic stress on the tissue in the mesh holes and the adjacent tissue, resulting in tissue damage and implant exposure.

Comparative study of biomechanical stability of resorbable and titanium fixation systems after sagittal split ramus osteotomy with a novel designed in-vitro testing unit

IntroductionSagittal split ramus osteotomy (SSRO) is one of the most popular surgical procedures for correction of mandibular deformities. Several clinical and biomechanical studies exist in the literature which, comparing the stability of different osteosynthesis materials and techniques, were performed using two or three-point biomechanical test models. The aim of this study was to compare the stability of biodegradable and titanium materials for SSRO on one-piece polyurethane mandible samples which were fixed in a novel designed 6-point testing unit. Materials and methods16 polyurethane one piece replicas of human mandibles were used and bilateral SSRO were performed by the manufacturer according to Dal Pont modification. Mandibles were fixed with titanium and PLLA/PGA fixation materials. Displacement amounts were measured under loading forces using a non-contact extensometer, and strain values at the screws were recorded by strain gauges. ResultsBicortical titanium screws (Group 2) showed significantly lower displacement values, while bicortical PLLA/PGA screws (group 4) showed significantly higher displacement values at 40–360 N forces. (p < 0.05). The highest strain value was measured on screws that were inserted upright in a proximal segment near the osteotomy line. ConclusionTo achieve more realistic results in biomechanical studies, test models should imitate jaw movements and test environments should be as similar as possible to physiological conditions. Newly designed six-point testing units will contribute to future biomechanical studies.

Healing at the Interface Between Autologous Block Bone Grafts and Recipient Sites Using n-Butyl-2-Cyanoacrylate Adhesive as Fixation: Histomorphometric Study in Rabbits.

The aim of the present split-mouth (split-plot) study was to describe the sequential healing in the interface between autologous bone grafts and recipient parent bone, fixed using an n-butyl-2-cyanoacrylate adhesive with or without an additional titanium fixation screw. Bone grafts were collected from the calvaria and fixed to the lateral aspect of the mandible in 24 rabbits. The cortical layers of the recipient sites were perforated, and the grafts were randomly fixed using an n-butyl-2-cyanocrylate adhesive, either alone or in conjunction with a 1.5 mm × 6.0 mm titanium fixation screw. The animals were sacrificed after 3, 7, 20, and 40 days, and histomorphometric evaluations of the interface between graft and parent bone were performed. Only 2 of 6 grafts in each group were partially incorporated to the parent bone after 40 days of healing. The remaining grafts were separated from the parent bone by adhesive and connective tissue. It was concluded that the use of n-butyl-2-cyanoacrylate as fixation of an autologous bone graft to the lateral aspect of the mandible was able to maintain the fixation over time but did not incorporate the graft to the recipient sites. Use of fixation screws did not improve the healing.

Possibility of quantitative T2-mapping MRI of cartilage near metal in high tibial osteotomy: A human cadaver study.

T2-mapping is a widely used quantitative MRI technique in osteoarthritis research. An important challenge for its application in the context of high tibial osteotomy (HTO) is the presence of metallic fixation devices. In this study, we evaluated the possibility of performing T2-mapping after a HTO, by assessing the extent of magnetic susceptibility artifacts and the influence on T2 relaxation times caused by two commonly used fixation devices. T2-mapping with a 3D fast spin-echo sequence at three Tesla was performed on 11 human cadaveric knee joints before and after implantation of a titanium plate and screws (n = 5) or cobalt chrome staples (n = 6). Mean T2 relaxation times were calculated in six cartilage regions, located in the distal and posterior cartilage of femoral condyles and the cartilage of tibial plateaus, both medially and laterally. T2 relaxation times before and after the implantation were compared with paired t-tests and Wilcoxon rank tests. Due to the extent of the magnetic susceptibility artifact, it was not possible to segment the knee cartilage and thus calculate T2 relaxation times in the lateral weight-bearing femoral and tibial cartilage regions only in the cobalt chrome group. In all cartilage regions of the titanium implanted knees and those unaffected by artifacts due to cobalt chrome implants, T2 relaxation times did not significantly differ between the two scans. Our results suggest that accurate T2-mapping after a HTO procedure is possible in all areas after implantation of a titanium fixation device and in most areas after implantation of a cobalt chrome fixation device. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1206-1212, 2018.

Resorbable versus titanium plates for orthognathic surgery.

Recognition of some of the limitations of titanium plates and screws used for the fixation of bones has led to the development of plates manufactured from bioresorbable materials. Whilst resorbable plates appear to offer clinical advantages over metal plates in orthognathic surgery, concerns remain about the stability of fixation and the length of time required for their degradation and the possibility of foreign body reactions. This review compares the use of titanium versus bioresorbable plates in orthognathic surgery and is an update of the Cochrane Review first published in 2007. To compare the effects of bioresorbable fixation systems with titanium systems used during orthognathic surgery. Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 January 2017); the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 11) in the Cochrane Library (searched 20 January 2017); MEDLINE Ovid (1946 to 20 January 2017); and Embase Ovid (1980 to 20 January 2017). We searched the US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (clinicaltrials.gov; searched 20 January 2017), and the World Health Organization International Clinical Trials Registry Platform (searched 20 January 2017) for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Randomised controlled trials comparing bioresorbable versus titanium fixation systems used for orthognathic surgery in adults. Two review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies. We resolved disagreement by discussion. Clinical heterogeneity between the included trials precluded pooling of data, and only a descriptive summary is presented. This review included two trials, involving 103 participants, one comparing titanium with resorbable plates and screws and the other titanium with resorbable screws. Both studies were at high risk of bias and provided very limited data for the primary outcomes of this review. All participants in one trial suffered mild to moderate postoperative discomfort with no statistically significant difference between the two plating groups at different follow-up times. Mean scores of patient satisfaction were 7.43 to 8.63 (range 0 to 10) with no statistically significant difference between the two groups throughout follow-up. Adverse effects reported in one study were two plate exposures in each group occurring between the third and ninth months. Plate exposures occurred mainly in the posterior maxillary region, except for one titanium plate exposure in the mandibular premolar region. Known causes of infection were associated with loosened screws and wound dehiscence with no statistically significant difference in the infection rate between titanium (3/196), and resorbable (3/165) plates. We do not have sufficient evidence to determine if titanium plates or resorbable plates are superior for fixation of bones after orthognathic surgery. This review provides insufficient evidence to show any difference in postoperative pain and discomfort, level of patient satisfaction, plate exposure or infection for plate and screw fixation using either titanium or resorbable materials.

The Redox Balance in Erythrocytes, Plasma, and Periosteum of Patients with Titanium Fixation of the Jaw.

Titanium miniplates and screws are commonly used for fixation of jaw fractured or osteotomies. Despite the opinion of their biocompatibility, in clinical practice symptoms of chronic inflammation around the fixation develop in some patients, even many years after the application of miniplates and screws. The cause of these complications is still an unanswered question. Taking into account that oxidative stress is one of the toxic action of titanium, we have evaluated the antioxidant barrier as well as oxidative stress in the erythrocytes, plasma and periosteum covering the titanium fixation of the jaw. The study group was composed of 32 patients aged 20–30 with inserted miniplates and screws. The antioxidant defense: catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase-1 (SOD1), uric acid (UA), total antioxidant capacity (TAC), as well as oxidative damage products: advanced oxidation protein products (AOPP), advanced glycation end products (AGE), dityrosine, kynurenine, N-formylkynurenine, tryptophan, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), total oxidant status (TOS), and oxidative status index (OSI) were evaluated. SOD1 activity (↓37%), and tryptophan levels (↓34%) showed a significant decrease while AOPP (↑25%), TOS (↑80%) and OSI (↑101%) were significantly elevated in maxillary periosteum of patients who underwent bimaxillary osteotomies as compared to the control group. SOD-1 (↓55%), TAC (↓58.6%), AGE (↓60%) and N-formylkynurenine (↓34%) was statistically reduced while AOPP (↑38%), MDA (↑29%), 4-HNE (↑114%), TOS (↑99%), and OSI (↑381%) were significantly higher in the mandibular periosteum covering miniplates/screw compared with the control tissues. There were no correlations between antioxidants and oxidative stress markers in the periosteum of all patients and the blood. As exposure to the Ti6Al4V titanium alloy leads to disturbances of redox balance in the periosteum surrounding titanium implants of the maxilla and the mandible so antioxidant supplementation should be recommended to the patients undergoing treatment of dentofacial deformities with the use of titanium implants. The results we obtained may also indicate a need to improve the quality of titanium jaw fixations through increase of TiO2 passivation layer thickness or to develop new, the most highly biodegradable materials for their production.

Comparison of the long-term clinical performance of a biodegradable and a titanium fixation system in maxillofacial surgery: A multicenter randomized controlled trial.

BackgroundBiodegradable fixation systems could reduce or eliminate problems associated with titanium removal of implants in a second operation.AimThe aim of this study was to compare the long-term (i.e. >5 years postoperatively) clinical performance of a titanium and a biodegradable system in oral and maxillofacial surgery.Materials and methodsThe present multicenter Randomized Controlled Trial (RCT) was performed in four hospitals in the Netherlands. Patients treated with a bilateral sagittal split osteotomy (BSSO) and/or a Le Fort-I osteotomy, and those treated for fractures of the mandible, maxilla, or zygoma were included from December 2006 to July 2009. The patients were randomly assigned to either a titanium (KLS Martin) or a biodegradable group (Inion CPS).ResultsAfter >5 years postoperatively, plate removal was performed in 22 of the 134 (16.4%) patients treated with titanium and in 23 of the 87 (26.4%) patients treated with the biodegradable system (P = 0.036, hazard ratio (HR) biodegradable (95% CI) = 2.0 (1.05–3.8), HR titanium = 1). Occlusion, VAS pain scores, and MFIQ showed good and (almost) pain free mandibular function in both groups.ConclusionIn conclusion, the performance of the Inion CPS biodegradable system was inferior compared to the KLS Martin titanium system regarding plate/screws removal in the abovementioned surgical procedures.Trial registrationhttp://controlled-trials.com ISRCTN44212338.

Incidence and risk factors predisposing plate removal following orthognathic surgery

The aim of this study was to investigate the incidence and reasons for titanium fixation plate removal following orthognathic surgery, identify risk factors predisposing removal, and explore if discomfort was reduced postoperatively. Medical records of 404 consecutive cases were retrospectively reviewed. All patients received a questionnaire for follow-up, and 323 patients answered the questionnaire, thus forming the sample group. Of all the responding patients, 15% had plates removed, and 92% of these patients experienced relief from discomfort after removal of the plates. Infection was the most common reason for plate removal (10%). Smoking (hazard ratio 2.74) and surgery performed in the mandible (hazard ratio 2.40) increased the need for plate removal. For each plate added in the mandible, the risk for removal increased by 34%. Smoking, osteotomies, and additional numbers of plates in the mandible resulted in a higher incidence of plate removal. Most of the patients experienced relief from discomfort after plate removal.

Long-term clinical performance of a biodegradable versus a titanium fixation system in maxillofacial surgery: a multicentre randomised clinical trial

Long-term clinical performance of a biodegradable versus a titanium fixation system in maxillofacial surgery: a multicentre randomised clinical trial

Comparison of functional outcomes and patient-reported satisfaction between titanium and absorbable plates and screws for fixation of mandibular fractures: A one-year prospective study

PurposeThe aim of this study is to compare the 1-year functional outcomes and patient-reported satisfaction in treating mandibular fractures between resorbable and titanium fixation devices. Materials and methodsA 1-year prospective study was conducted; 41 consecutive patients presenting with mandibular fractures were included. A resorbable system was used in 21 patients, while in 20 patients a titanium fixation device was used. Functional outcome was evaluated objectively at several time points (2, 4 and 6 weeks, 3 and 6 months, and 1 year after surgery). Bite forces over molars and incisors, mouth opening distance, occlusal status, operation time, fee for implants, bone healing and plate-associated complications were evaluated. Functional and overall satisfaction was measured by patients themselves subjectively. ResultsA statistical difference was found only in maximal mouth opening and molar bite force, both greater for the titanium group in the 2-week time point, achieving comparable measurements in subsequent ones. This coincides with the patient-reported statistically lower satisfaction rates. The cost of the resorbable device was nearly 3 times more expensive than the titanium devices. ConclusionResorbable fixation can achieve stability of bone healing at 1 year postoperatively, with functional and satisfaction outcomes comparable to those associated with titanium hardware from the fourth week postoperatively, while yielding unique advantages.

Biochemical Mechanism of Titanium Fixation into Living Bone: Acid Soluble Phosphoproteins in Bone Binds with Titanium and Induced Endochondral Ossification in vivo

Biochemical Mechanism of Titanium Fixation into Living Bone: Acid Soluble Phosphoproteins in Bone Binds with Titanium and Induced Endochondral Ossification in vivo

Clinical features and surgical outcomes of pediatric spinal meningiomas

Objective To investigate the clinical features and surgical outcomes of pediatric spinal meningiomas in order to provide evidence for the clinical diagnosis and treatment. Methods The clinical data of 12 children (≤15 ys) with spinal meningiomas admitted to the Department of Neurosurgery, Beijing Tiantan Hospital from January 2008 to December 2015 were analyzed retrospectively. The lateral position was used for all patients and tumors were resected under microscope by posterior midline approach. Among them, 7 patients underwent laminectomy and the remaining 5 received laminoplasty with titanium fixation. Intraoperative electrophysiological monitoring, including sensation and motor evoked potentials, was applied to avoid neurological function deficits. Results Grade Ⅰ and Ⅱ resections by the Simpson criteria were performed in 9 out of 12 cases, and Grade IV resection in the remaining 3 cases. Postoperative remission of symptoms was reported in 8 patients. Grade I meningiomas proved by postoperative pathological examination accounted for 8/12 in this series, and Grade II meningiomas were reported in 4 other cases. During follow-up, tumor recurrence was found in 5 patients and two patients underwent second surgical operation. None of the patients were administered post-operative radiotherapy-or chemotherapy. Conclusions Pediatric spinal meningiomas are relatively uncommon and inclined to be associated with neurofibromatosis type 2. The complete resection rate is relatively low for pediatric spinal meningiomas thus the tumors have relatively high possibility of recurrence. Thorough preoperative examinations and sufficient extent of resection would help improve the surgical outcomes. Key words: Spinal canal; Meningioma; Child; Disease attributes; Surgery

Removal of symptomatic titanium fixation plates after craniotomy.

Titanium fixation plates are routinely used for rigid fixation of bone flaps after craniotomy. In craniofacial surgery or after craniotomy involving orbitozygomatic osteotomies, these plates are occasionally removed because of infection, pain, protrusion, soft tissue erosion, and plate malfunction. However, plate removal because of pain and protrusion after craniotomy without orbitozygomatic osteotomy has rarely been reported. A retrospective analysis of all patients who underwent removal of cranial fixation plates after craniotomy, performed by the senior authors at one institution between 2014 and 2016, was conducted. A total of 319 patients underwent bone flap fixation after craniotomy using cranial fixation plates between 2014 and 2016. Five of those patients (1.6%) had their cranial plates removed because of pain and protrusion. An additional four patients had a cranial fixation plate removed during that time frame with the original craniotomy performed before 2014. All nine patients had immediate resolution of symptoms after plate removal. We report our experience with cranial fixation plate removal because of pain and protrusion in patients who underwent craniotomy without orbitozygomatic osteotomy, particularly frontotemporal craniotomy. In an attempt to reduce this complication, we recently stopped placing a full-size burr hole in the keyhole area of a frontotemporal craniotomy, eliminating the need for a titanium burr hole cover plate.

Treatment of fractures of the mandibular condylar head with ultrasound-activated resorbable pins: early clinical experience

Controversy continues about the benefits and disadvantages of open reduction and internal fixation of fractures of the condylar head. Once a decision to treat surgically has been made, an appropriate method of fixation must be chosen. Standard titanium fixation has a number of complications, including the risk of protrusion of the screw beyond the condylar head and the possible need for removal later. Resorbable fixation is an alternative, and ultrasound-activated resorbable pins are a new innovation. We have treated a series of 15 patients with 17 fractures of the condylar head, in which the use of ultrasound-activated resorbable fixation has provided adequate strength and stability during early healing. Complications included technical difficulties in achieving complete anatomical reduction as a result of fragmentation of the condylar head, and three facial nerve palsies, two of which recovered within three months. No pins failed, and there was no sign of instability during healing.

MicroCT assessment of bone microarchitecture in implant sites reconstructed with autogenous and xenogenous grafts: a pilot study.

To assess bone microarchitecture in maxillary sites grafted with autogenous or xenogenous grafts as well as to demonstrate the usefulness of microCT in dental implant research. Samples (n=12) consisting of titanium fixation screws covered by at least 0.5-1mm of human bone were obtained from 17 sites grafted with autogenous or xenogenous materials and prepared for microCT scanning and conventional histology. Bone histomorphometric parameters were evaluated in three distinct regions (graft region, transitional region, and native bone region). Three-dimensional (3D) bone-to-implant contact (BIC) calculation was performed using microCT data. Histological sections were used to calculate two-dimensional (2D) BIC percentages, which were compared with values obtained from 2D microCT images. Histomorphometric parameters varied according to the type of graft used, but sites reconstructed with autogenous bone showed higher mean values in general. In autograft samples, indices for parameters such as Tb.Th and Tb.Sp were significantly different when the native bone region was compared to the graft region. While a higher mean 3D BIC was found in the native bone region for both graft materials, significant BIC differences were absent when graft types were compared. The 2D BIC percentages obtained from histological and microCT images were similar. Autografts outperformed the xenogenous material used in this study concerning the histomorphometric parameters assessed. While graft type did not seem to influence 3D BIC, the native bone region showed the highest BIC percentages when compared to the other regions in both graft groups. In addition, 2D BIC ratios were similar regardless of graft material or image source (histological sections x microCT slices). Taken together, our findings suggest that microCT is an effective tool for 2D and 3D histomorphometric and BIC assessments in dental implant research.

Posterior Titanium Screw Fixation without Debridement of Infected Tissue for the Treatment of Thoracolumbar Spontaneous Pyogenic Spondylodiscitis.

Study DesignRetrospective study.PurposeThe aim of our study was to analyze the safety and effectiveness of posterior pedicle screw fixation for treatment of pyogenic spondylodiscitis (PSD) without formal debridement of the infected tissue.Overview of LiteraturePosterior titanium screw fixation without formal debridement of the infected tissue and anterior column reconstruction for the treatment of PSD is still controversial.MethodsFrom March 2008 to June 2013, 18 patients with PSD underwent posterior titanium fixation with or without decompression, according to their neurological deficit. Postero-lateral fusion with allograft transplantation alone or bone graft with both the allogenic bone and the autologous bone was also performed. The outcome was assessed using the visual analogue scale (VAS) for pain and the Frankel grading system for neurological status. Normalization both of C-reactive protein (CRP) and erythrocyte sedimentation rate was adopted as criterion for discontinuation of antibiotic therapy and infection healing. Segmental instability and fusion were also analyzed.ResultsAt the mean follow-up time of 30.16 months (range, 24–53 months), resolution of spinal infection was achieved in all patients. The mean CRP before surgery was 14.32±7.9 mg/dL, and at the final follow-up, the mean CRP decreased to 0.5±0.33 mg/dL (p <0.005). Follow-up computed tomography scan at 12 months after surgery revealed solid fusion in all patients. The VAS before surgery was 9.16±1.29 and at the final follow-up, it improved to 1.38±2.03, which was statistically significant (p <0.05). Eleven patients out of eighteen (61.11%) with initial neurological impairment had an average improvement of 1.27 grades at the final follow-up documented with the Frankel grading system.ConclusionsPosterior screw fixation with titanium instrumentation was safe and effective in terms of stability and restoration of neurological impairment. Fixation also rapidly reduced back pain.