Dynamic study about metal release from titanium miniplates in maxillofacial surgery

Cross-Sectional Study of Serum Metal Ions in Patients With Metal Implants in the Maxillofacial Region

Purpose

The purpose of the present study was to measure the serum metal ion levels (titanium, cobalt, chromium) in patients who have metal implants in the maxillofacial region.

Methods

The investigators implemented a cross sectional study on patients treated with procedures requiring metal implants for management of maxillofacial trauma, fixation for orthognathic surgery, and total temporomandibular joint replacement (TJR). Inductively coupled plasma mass spectrometry was used as an analytical method to detect metal ions in serum samples.

Results

The study comprised of 50 patients who were divided into 4 groups- group I- total TJR (n = 18), group II- orthognathic (n = 8), group III- trauma (n = 8), and group IV- control (n = 16). The mean values of metal ions level were raised than the control group.

Conclusion

The present study's results suggest a rise in serum metal ion levels after the metal implantation in maxillofacial region. None of the patients had any abnormal signs and symptoms due to raised metal levels. Further studies are warranted to correlate the serum metal ion levels and their clinical relevance.

Titanium or Biodegradable Osteosynthesis in Maxillofacial Surgery? In Vitro and In Vivo Performances

Osteosynthesis systems are used to fixate bone segments in maxillofacial surgery. Titanium osteosynthesis systems are currently the gold standard. However, the disadvantages result in symptomatic removal in up to 40% of cases. Biodegradable osteosynthesis systems, composed of degradable polymers, could reduce the need for removal of osteosynthesis systems while avoiding the aforementioned disadvantages of titanium osteosyntheses. However, disadvantages of biodegradable systems include decreased mechanical properties and possible foreign body reactions. In this review, the literature that focused on the in vitro and in vivo performances of biodegradable and titanium osteosyntheses is discussed. The focus was on factors underlying the favorable clinical outcome of osteosyntheses, including the degradation characteristics of biodegradable osteosyntheses and the host response they elicit. Furthermore, recommendations for clinical usage and future research are given. Based on the available (clinical) evidence, biodegradable copolymeric osteosyntheses are a viable alternative to titanium osteosyntheses when applied to treat maxillofacial trauma, with similar efficacy and significantly lower symptomatic osteosynthesis removal. For orthognathic surgery, biodegradable copolymeric osteosyntheses are a valid alternative to titanium osteosyntheses, but a longer operation time is needed. An osteosynthesis system composed of an amorphous copolymer, preferably using ultrasound welding with well-contoured shapes and sufficient mechanical properties, has the greatest potential as a biocompatible biodegradable copolymeric osteosynthesis system. Future research should focus on surface modifications (e.g., nanogel coatings) and novel biodegradable materials (e.g., magnesium alloys and silk) to address the disadvantages of current osteosynthesis systems.

A Narrative Review of u-HA/PLLA, a Bioactive Resorbable Reconstruction Material: Applications in Oral and Maxillofacial Surgery

The advent of bioresorbable materials to overcome limitations and replace traditional bone-reconstruction titanium-plate systems for bone fixation, thus achieving greater efficiency and safety in medical and dental applications, has ushered in a new era in biomaterial development. Because of its bioactive osteoconductive ability and biocompatibility, the forged composite of uncalcined/unsintered hydroxyapatite and poly L-lactic acid (u-HA/PLLA) has attracted considerable interest from researchers in bone tissue engineering, as well as from clinicians, particularly for applications in maxillofacial reconstructive surgery. Thus, various in vitro studies, in vivo studies, and clinical trials have been conducted to investigate the feasibility and weaknesses of this biomaterial in oral and maxillofacial surgery. Various technical improvements have been proposed to optimize its advantages and limit its disadvantages. This narrative review presents an up-to-date, comprehensive review of u-HA/PLLA, a bioactive osteoconductive and bioresorbable bone-reconstruction and -fixation material, in the context of oral and maxillofacial surgery, notably maxillofacial trauma, orthognathic surgery, and maxillofacial reconstruction. It simultaneously introduces new trends in the development of bioresorbable materials that could used in this field. Various studies have shown the superiority of u-HA/PLLA, a third-generation bioresorbable biomaterial with high mechanical strength, biocompatibility, and bioactive osteoconductivity, compared to other bioresorbable materials. Future developments may focus on controlling its bioactivity and biodegradation rate and enhancing its mechanical strength.

Design approaches and challenges for biodegradable bone implants: a review

Introduction: Biodegradable materials have been at the forefront of cutting-edge research and offer a truly viable option in the designing and manufacturing of bone implants in biomedical engineering. Most research regarding these materials has focused on their biological characteristics and mechanical behavior vis-à-vis nonbiodegradable (NB) materials; but the design aspects and parametric configurations of biodegradable bone implant have somehow not received as much attention as they deserved.Area covered: This review aims to develop insight into the parametrically conceptualized design of biodegradable bone implant and takes into due consideration the characteristics of bone-biodegradable implant interface (BBII), design techniques employed for conventionally used bone implants to optimize parameters using standard test methods, traditional design, and finite element analysis approaches for implant and healing behavior, manufacturing techniques, real-time surgical simulations, and so on.Expert opinion: Some successful and conventionally used NB bone implants do not dissolve or degrade with time and require removal through a complicated surgery after fulfilling the intended objectives. These bone implants should be reconceptualized and designed with an appropriate biodegradable material while paying due attention to all factors/parameters involved and striking a balance between these factors with the ultimate objective of fulfilling all desired orthopedic requirements.

Early Pediatric Multiple Facial Fractures Treatment With Resorbable Fixation

ABSTRACT

The facial skeleton in pediatric patients can undergo several changes during development, according to their growth zones and the traumas they suffer. Thus, some of these traumas can lead to multiple complications if not treated properly. Epidemiology can vary according to the social, cultural, and environmental aspects of each individual. Therefore, each case must be treated individually, and it is important to consider age-specific aspects, such as the high osteogenic potential, which leads to faster bone healing. The use of resorbable fixation materials in facial fractures of pediatric patients is widespread, with good acceptance and great advantages over conventional titanium materials, mainly for the elimination of a second surgery to remove the materials. The present study aims to report a series of clinical cases of infants, who suffered trauma and evolved with fractures in the facial bones. Surgical treatment was instituted to reduce and fix fractures, using the resorbable system. Patients are followed up with periodic outpatient follow-up visits and have a good case evolution.

The Implications of Titanium Alloys Applied in Maxillofacial Osteosynthesis

Titanium alloys are known for their biological, mechanical and chemical properties, which have successfully expanded their use in the maxillofacial field. The internal fixation using titanium miniplates and screws offer a new perspective for the treatment of trauma and in orthognathic surgery and maxillofacial oncology. Although, titanium is highly recommended for its excellent biocompatibility, recent research has focused on identifying the potential local and general implications of the interactions between the human tissue and the metallic particles. This present review aims to outline the existing tissue changes, cellular alterations and future perspectives regarding the use of titanium-based alloys as osteosynthesis materials, taking into consideration the existing present debate whether the routinely removal of these materials should be an indication.

Removal of dental alloys and titanium attenuates trace metals and biological effects on liver and kidney

To determine whether the potential effects on liver and kidney caused by dental alloys could be reduced or terminated by the removal of nickel-chromium (Ni-Cr) alloy, cobalt-chromium (Co-Cr) alloy, and commercially pure titanium (CP-Ti), they were placed in the cheek pouches of Syrian hamsters according to ISO 10993-10. Then, the peak/plateau and end times of trace metals in the blood were determined with or without the removal of the dental alloys. Based on these time points, the trace metals and their effects on liver and kidney were examined. We found that trace metals released from these dental alloys and titanium were accumulated transiently in the blood, liver, and kidney but had no effect on the histopathology of the liver or kidney. Although the functions of the liver and kidney were compromised, the function of these tissues seemed to be clinically acceptable compared to those in control Syrian hamsters. In addition, the apoptotic effect on renal cells was terminated by removing the Ni-Cr and Co-Cr alloys, and that on hepatocytes was also eliminated by removing the Ni-Cr alloy. In contrast, the effect of the Co-Cr alloy on hepatocytes was temporary and recovered by itself. Taken together, Ni- and Co-based dental alloys and titanium have no effect on the histopathology or function of liver and kidney. Moreover, Ni-Cr and Co-Cr alloys induce transient trace metal accumulation and apoptotic effects in liver and kidney, which can be reduced or terminated by the removal of the alloys, while CP-Ti shows favorable biocompatibility.

Miniplate removal in operated cases of maxillofacial region in a dental institute in Rajasthan, India

Background

The long term management of miniplate fixation osteosynthesis remains debatable and controversial with few authors advocating routine removal of the miniplates after 3–6 months of placement, while others recommend retention of the miniplates unless their removal is clinically indicated.

Objective

The aim was to study the incidence, indications, time gap, role of metallic composition and site of removal of miniplates in operated cases of maxillofacial region over a two-year period.

Methods

Patients undergoing removal of miniplates over 2-year period were studied and evaluated regarding the number of miniplates removed, time gap present between fixation and removal of miniplates, indications for removal, metallic composition of miniplates removed, sites of removal and complications. Correlations between indications for miniplate removal based upon time gap, metallic composition, age group and number of miniplates present were determined using Chi-square test. Correlation between metallic composition of miniplate and time gap was also determined using Chi-square test.

Results

The miniplates were removed in 20 patients (16 males and 4 females). Most common indication for removal was infection (45%). Forty-five percent of the patients underwent miniplate removal within 1 year of placement. Thirty-four miniplates and 118 screws were removed. The correlation between indications for miniplate removal and time gap was found to be statistically significant (P = 0.04).

Conclusion

Most of the hardware removal is performed subsequent to complications associated with hardware and local factors play more important role than metallic composition. Routine asymptomatic miniplates do not require removal and is not recommended.

Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis

BACKGROUND

The goal of treatment for zygomaticomaxillary (ZM) complex (ZMC) fractures is to achieve stability and restore aesthetic appearance through three-dimensional reduction and rigid fixation. The purpose of this study was to evaluate the stability and aesthetic appearance outcomes of one-point fixation using a three-dimensional photogrammetric analysis.

METHODS

From March 2014 to December 2014, 34 patients with ZMC fractures were treated by one-point fixation in the ZM buttress using unsintered hydroxyapatite (u-HA)/poly-L-lactide (PLLA) plates. Differences in soft tissue inter-malar height between the fractured side and unfractured sides were evaluated using photogrammetric analysis with a three-dimensional camera (Morphius®) at the preoperative and 1 week, 1 and 3 months after surgery. The differences in bony inter-malar height between the fractured and unfractured sides were evaluated using computer tomography at the pre-operative and 6 months after surgery. The paired t-test was used to compare differences in malar height.

RESULTS

Six months after surgery, 34 patients achieved satisfactory bony stability and symmetric malar appearances. Comparisons of differences in soft-tissue inter-malar height revealed statistically significant differences between the pre-operative period and 1 week and 1 month after surgery (p < .01). There was no statistically significant difference between 1 and 3 months after surgery. Comparison of differences in bony inter-malar height revealed a statistically significant difference between before and 6 months after surgery (p < .01).

CONCLUSIONS

When we conducted a three-dimensional photogrammetric analysis, although it has restricted surgical indications, one-point fixation of the ZM buttress using an u-HA / PLLA plate yielded reliable, satisfactory, and safe clinical results in patients with ZMC fractures.

CLINICAL QUESTION / LEVEL OF EVIDENCE

Therapeutic, III.

Hybrid fracture fixation systems developed for orthopaedic applications: A general review

Orthopaedic implants are applied daily in our orthopaedic clinics for treatment of musculoskeletal injuries, especially for bone fracture fixation. To realise the multiple functions of orthopaedic implants, hybrid system that contains several different materials or parts have also been designed for application, such as prosthesis for total hip arthroplasty. Fixation of osteoporotic fracture is challenging as the current metal implants made of stainless steel or titanium that are rather rigid and bioinert, which are not favourable for enhancing fracture healing and subsequent remodelling. Magnesium (Mg) and its alloys are reported to possess good biocompatibility, biodegradability and osteopromotive effects during its in vivo degradation and now tested as a new generation of degradable metallic biomaterials. Several recent clinical studies reported the Mg-based screws for bone fixation, although the history of testing Mg as fixation implant was documented more than 100 years ago. Truthfully, Mg has its limitations as fixation implant, especially when applied at load-bearing sites because of rather rapid degradation. Currently developed Mg-based implants have only been designed for application at less or non-loading-bearing skeletal site(s). Therefore, after years research and development, the authors propose an innovative hybrid fixation system with parts composed of Mg and titanium or stainless steel to maximise the biological benefits of Mg; titanium or stainless steel in this hybrid system can provide enough mechanical support for fractures at load-bearing site(s) while Mg promotes the fracture healing through novel mechanisms during its degradation, especially in patients with osteoporosis and other metabolic disorders that are unfavourable conditions for fracture healing. This hybrid fixation strategy is designed to effectively enhance the osteoporotic fracture healing and may potentially also reduce the refracture rate. The translational potential of this article: This article systemically reviewed the combination utility of different metallic implants in orthopaedic applications. It will do great contribution to the further development of internal orthopaedic implants for fracture fixation. Meanwhile, it also introduced a titanium-magnesium hybrid fixation system as an alternative fixation strategy, especially for osteoporotic patients.

Overview of innovative advances in bioresorbable plate systems for oral and maxillofacial surgery

Maxillofacial osteosynthetic surgeries require stable fixation for uneventful boney healing and optimal remodeling. Although conventional titanium plates and screws for osteofixation are considered the gold standard for rigid fixation in maxillofacial surgeries, bioresorbable implants of plates and screw systems are commonly used for various maxillofacial osteosynthetic surgeries such as orthognathic surgery, maxillofacial fractures, and reconstructive surgery. Titanium plates are limited by their palpability, mutagenic effects, and interference with imaging, which may lead to the need for subsequent removal; the use of a biologically resorbable osteofixation system could potentially address these limitations. However, several problems remain including fundamental issues involving decreased mechanical strength and stability, slow biodegradation, complex procedures, and the available bioresorbable implant materials. Major advances in bioresorbable plate systems have been made with the use of bioactive/resorbable osteoconductive materials and an accelerator of bioresorption, such as polyglycolic acid. This report presents an overview of currently available resorbable implant materials and their applications, with a focus on recent innovative advances and new developments in this field.

Titanium: a review on exposure, release, penetration, allergy, epidemiology, and clinical reactivity

Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations for detection of type IV hypersensitivity is currently inadequate for Ti. Although several other methods for contact allergy detection have been suggested, including lymphocyte stimulation tests, none has yet been generally accepted, and the diagnosis of Ti allergy is therefore still based primarily on clinical evaluation. Reports on clinical allergy and adverse events have rarely been published. Whether this is because of unawareness of possible adverse reactions to this specific metal, difficulties in detection methods, or the metal actually being relatively safe to use, is still unresolved.

Potential release of in vivo trace metals from metallic medical implants in the human body: from ions to nanoparticles--a systematic analytical review

Metal ion release from metallic materials, e.g. metallic alloys and pure metals, implanted into the human body in dental and orthopedic surgery is becoming a major cause for concern. This review briefly provides an overview of both metallic alloys and pure metals used in implant materials in dental and orthopedic surgery. Additionally, a short section is dedicated to important biomaterials and their corrosive behavior in both real solutions and various types of media that model human biological fluids and tissues. The present review gives an overview of analytical methods, techniques and different approaches applied to the measurement of in vivo trace metals released into body fluids and tissues from patients carrying metal-on-metal prostheses and metal dental implants. Reference levels of ion concentrations in body fluids and tissues that have been determined by a host of studies are compiled, reviewed and presented in this paper. Finally, a collection of published clinical data on in vivo released trace metals from metallic medical implants is included.

Complications of absorbable fixation in maxillofacial surgery: a meta-analysis

BACKGROUND

The use of titanium during maxillofacial fixation is limited due to its palpability, mutagenic effects and interference with imaging, which lead to the requirement for subsequent removal. The use of a biologically absorbable fixation material will potentially eliminate these limitations. In this meta-analysis, we analyzed the complications of absorbable fixation in maxillofacial surgery.

METHODS

We performed a systematic search of PubMed, Embase, Cochrane Central Register of Systematic Reviews and Cochrane Central Register of Controlled Trials for trials published through December 2012. Data extracted from literature were analyzed with Review manager 5.0.24.

RESULTS

Relevant data was extracted from 20 studies (1673 participants) and revealed that patients in the absorbable group had significantly more complications than those in the titanium group (RR = 1.20; 95% CI: 1.02-1.42; P = 0.03) in all enrolled maxillofacial surgeries. For bimaxillary operation subgroup, the absorbable fixation group did not have a significant increase in complications when compared with the titanium group (RR = 1.89; 95% CI: 0.85-4.22; P = 0.12). There was no significant difference observed between the absorbable and titanium groups receiving a bilateral sagittal split ramus osteotomy (BSSRO) (RR = 1.45; 95% CI: 0.84-2.48; P = 0.18) and Le Fort I osteotomy (RR = 0.65; 95% CI: 0.34-1.23; P = 0.18). The combined results of the five trials revealed that the absorbable group had a significantly lower rate of complications compared to the titanium group (RR = 0.71; 95% CI: 0.52-0.97; P = 0.03) in fracture fixation.

CONCLUSION

This meta-analysis shows that absorbable fixation systems used for fixation in maxillofacial surgery do not have adequate safety profiles. Subgroup indicated the safety of absorbable fixation systems was superior during fracture fixation. The absorbable fixation systems tend to have a similar favorable safety profile as titanium fixation during Le Fort I, bimaxillary operation and BSSRO.

Surgical treatment of facial fracture by using unsintered hydroxyapatite particles/poly l-lactide composite device (OSTEOTRANS MX(®)): a clinical study on 17 cases

BACKGROUND

In Japan we currently use absorption properties for facial fractures. OSTEOTRANS MX(®) (Takiron co., ltd, Japan) is an absorption device, which is called Super FIXSORB MX(®) in Japan. This absorbable osteosynthetic device constitutes unsintered hydroxyapatite particles/poly l-lactide (u-HA/PLLA) composites. This study focuses on reporting clinical cases of using OSTEOTRANS MX(®).

MATERIALS AND METHODS

Seventeen patients (16 men and 1 woman) aged 10-80 years (mean: 39.9 years, SD: ±20.7) with 86 fracture sites were treated. In all cases we used 1.0 mm plates and 5 mm or 7 mm screws. The postoperative observation period was 6-60 months (mean: 21.8 months, SD: ±14.5).

RESULTS

The fracture site recovered in all cases. Complications included one bone excess on the forehead and one foreign-body reaction on the frontozygomatic suture, but the fracture sites were recovered and had no problems. In the case with the longest observation time 60 months, the plate was almost fully absorbed. However, in other cases the plate was not fully absorbed because of a shorter observation time.

CONCLUSION

OSTEOTRANS MX(®) is a useful device because of its suitable intensity, thinness, radiopaque, and few complications. A longer observation time is required for a plate to be absorbed completely.

Resorbable implants in maxillofacial surgery: a reality check

BACKGROUND

Stability is the main feature of fixation techniques in fracture management modalities, in vogue today. One of the most significant landmarks in the armamentarium of maxillofacial fracture management has been the introduction of rigid internal fixation (RIF). The biomaterials used in RIF have seen a gradual change from Stainless steel to titanium due to the evidence based advantages of the latter. However, the inherent problems with metallic implants led to the introduction of resorbable polymers in RIF.

MATERIALS AND METHOD

This article evaluates the efficacy of these polymers in fixation of bone segments as compared to titanium fixation implants in 40 patients of zygomatic complex fractures. The study compared the clinical efficacy, technique, cost and time factors in the use of these two biomaterials.

RESULTS

The results showed very little difference after the use of these two biomaterials in spite of the increased time, technique sensitivity and cost of the resorbable system.

CONCLUSION

The argument for use of the resorbable fixation implants as a better alternative to titanium in maxillofacial fracture management seems overstated considering the insignificant differences in the results obtained but significant differences in the time taken and economics of the two biomaterials. The resorbabale system should ideally be restricted for use in pediatric craniofacial surgery.

Evaluation of Bioresorbable vis-à-vis Titanium Plates and Screws for Craniofacial Fractures and Osteotomies

BACKGROUND

Rigid internal fixation with metals is a reliable method of achieving osteosynthesis while allowing the patient passive or even functional loading of the fracture or osteotomised bone segments. The disadvantages with metals have led to the introduction of resorbable polymers in rigid internal fixation.

METHODS

This study was conducted to evaluate the efficacy of these polymers as compared to titanium in fixation of bone segments fixation in 40 patients of zygomatic complex fractures and craniosynostosis management. The cases were followed up for one year.

RESULT

The stability of the fixation was found to be comparable to metallic fixation though the armamentarium and procedure of fixation of resorbable system was more demanding and the technique sensitive.

CONCLUSION

The resorbable system is a good system for rigid internal fixation in specific conditions where muscular and stress forces are not a determining factor in fragment displacement.

Titanium allergy: could it affect dental implant integration?

PURPOSE

Degradation products of metallic biomaterials including titanium may result in metal hypersensitivity reaction. Hypersensitivity to biomaterials is often described in terms of vague pain, skin rashes, fatigue and malaise and in some cases implant loss. Recently, titanium hypersensitivity has been suggested as one of the factors responsible for implant failure. Although titanium hypersensitivity is a growing concern, epidemiological data on incidence of titanium-related allergic reactions are still lacking.

MATERIALS AND METHODS

A computer search of electronic databases primarily MEDLINE and PUBMED was performed with the following key words: 'titanium hypersensitivity', 'titanium allergy', 'titanium release' without any language restriction. Manual searches of the bibliographies of all the retrieved articles were also performed. In addition, a complementary hand search was also conducted to identify recent articles and case reports.

RESULTS

Most of the literature comprised case reports and prospective in vivo/in vitro trials. One hundred and twenty-seven publications were selected for full text reading. The bulk of the literature originated from the orthopaedic discipline, reporting wear debris following knee/hip arthroplasties. The rest comprised osteosynthesis (plates/screws), oral implant/dental materials, dermatology/cardiac-pacemaker, pathology/cancer, biomaterials and general reports.

CONCLUSION

This review of the literature indicates that titanium can induce hypersensitivity in susceptible patients and could play a critical role in implant failure. Furthermore, this review supports the need for long-term clinical and radiographic follow-up of all implant patients who are sensitive to metals. At present, we know little about titanium hypersensitivity, but it cannot be excluded as a reason for implant failure.

Peri-implant and systemic release of metallic elements following insertion of a mandibular modular endoprosthesis in Macaca fascicularis

The aim of this study was to assess the release of metal elements from a Ti6Al4V modular endoprosthesis for mandibular reconstruction. Ten monkeys were included, seven of the animals had an endoprosthesis inserted and three served as controls. Mucosa, regional lymph nodes and distant organs, were assessed after the implant had been in place for 12 months, using light (LM) and transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP). Blood was also drawn from all animals for elemental analysis using ICP. LM and TEM evaluation showed no detectable metal particles in the mucosa surrounding the endoprosthesis, nor in the regional lymph nodes and distant organs. Blood analysis revealed that titanium and vanadium were detectable in comparable amounts in the test (Ti: 1.63+/-0.54, Va: 0.42+/-0.08) as well as in the control group (Ti: 2.07+/-0.55, Va: 0.37+/-0.07). The amount of aluminum appeared to be higher in the control group (31.77+/-11.67) compared with the test group (20.41+/-9.13), but this difference was not statistically significant. ICP showed that no titanium, vanadium or aluminum was detectable in the mucosa surrounding the endoprosthesis. In addition, no titanium and vanadium were found in the lymph nodes and distant organs using ICP. On the other hand, using ICP, the aluminum content was found to be higher in the right regional lymph nodes and all examined distant organs as compared to the control group (lymph nodes: 11.55+/-22.15 vs. 0.36+/-0.61, lung: 6.24+/-11.28 vs. 1.40+/-2.15, liver: 1.66+/-0.99 vs. 0, kidney: 15.69+/-24.88 vs 0, spleen: 2.75+/-3.09 vs. 0.49+/-0.43). However, only for the kidney and liver the higher amount of aluminum was statistically significant. In conclusion, this study quantified the release of only aluminum in lymph nodes and distant organs, when using a modular endoprosthesis made of Ti-6Al-4V for mandibular reconstruction.

A retrieval study on morphological and chemical changes of titanium osteosynthesis plates and adjacent tissues

AIM

To examine (a) morphological and chemical changes of retrieved titanium osteosynthesis plates, (b) findings in adjacent soft tissues during plate removal and to evaluate possible correlations among the above-mentioned issues.

MATERIAL AND METHODS

Ninety-four osteosynthesis plates were retrieved, of which 60 were studied and evaluated (including the adjacent soft tissue) in more details, 4-36 months following osteosynthesis in 26 trauma cases, 12 orthognathic and 6 maxillofacial reconstructive cases. Selected clinical parameters during plate removal, were studied. Specialized laboratory methods including light and electron microscopy as well as spectrometry and X-ray microanalysis were used to analyse the retrieved material.

RESULTS

Plates showed major mechanical changes (scratches, scraping and deformation) without corrosion. Soft tissue inflammation-mainly mild and chronic-was found in 53 of 94 plates removed, a statistically significant percentage. Pigmented deposits in the soft tissues manifested only traces of titanium when analysed elementally. There was no statistically significant correlation between the laboratory findings of plates and tissues, or between plate morphology and clinical findings recorded.

CONCLUSIONS

According to the findings of this study, inflammation in tissues adjacent to osteosynthesis plates should not be attributed to mechanical changes in the plates. Pigmented tissue deposits were neither found to be titanium to the extent previously reported, nor were they correlated with tissue inflammation. These findings lead to the assumption that titanium plates do not have to be removed to avoid local inflammatory problems.

Self-reinforced biodegradable screw fixation compared with titanium screw fixation in mandibular advancement

PURPOSE

This report compares the skeletal stability and treatment outcomes of 2 similar cohorts undergoing bilateral sagittal osteotomies of the mandible for advancement. The study groups included patients stabilized with 2-mm self-reinforced polylactate (PLLDL 70/30), biodegradable screws (group B), and 2-mm titanium screws placed in a positional fashion (group T).

MATERIALS AND METHODS

Sixty-nine patients underwent bilateral sagittal osteotomies of the mandibular ramus for advancement utilizing an identical technique. There were 34 patients in group B and 35 patients in group T. Each patient had preoperative, immediate postoperative, splint out, and 1-year postoperative cephalometric radiographs available for analysis. The method of analysis and treatment outcomes parameters are identical to those previously used. Repeated measures analysis of variance was performed with means of fixation as the between-subject factor and time as the within subject factor. The level of significance was set at .01.

RESULTS

There were no clinical failures in group T and a single failure in group B. The average difference in stability between the groups is small and subtly different at the mandibular angle. The data documented similarity of the postsurgical changes in the 2 groups with the only statistically significant difference being the vertical position of the gonion (P < .001) and the mandibular plane angle (P < .01) with greater upward remodeling at gonion in group T.

CONCLUSIONS

Two-mm self-reinforced PLLDL (70/30) screws can be used as effectively as 2-mm titanium screws to stabilize the mandible after bilateral sagittal osteotomies for mandibular advancement. The difference in 1-year stability and outcome is minimal.

Inion biodegradable plates: the first century

I have used the Inion biodegradable plate system to treat patients with facial fractures who presented to Arrowe Park Hospital, Wirral between May 2003 and November 2004. I have inserted 100 miniplates (68 mandible, 15 maxilla, 12 zygomatic bone, 3 nose, and 2 thyroid cartilage). All the fractures healed.

Surrogate markers of health after titanium dental implant placement

PURPOSE

We investigated the effects of dental implants on patient health, as measured by commonly used surrogates of human homeostasis, including hepatic metabolic and synthetic ability, renal regulatory functions, bone turnover, clotting, infection, and inflammation.

MATERIALS AND METHODS

Patients enrolled had 1 to 3 mandibular uncoated, endosseous titanium dental implants placed and restored. Patients were evaluated serially over 6 months. Blood and urine tests were collected immediately before and 6 months after implant placement. Paired student t tests were used to compare quantified laboratory values. Nonquantified values were evaluated using the McNamara chi square analysis to assess patterns of change.

RESULTS

Thirty-one patients met the inclusion criteria. A total of 53 dental implants were placed. Three values were found to be significantly different between the 2 time periods: total protein (P < .008), lactate dehydrogenase (P < .002), and hematocrit (P < .017). Total protein and lactate dehydrogenase were within the laboratory range of normal and judged to be clinically nonsignificant. On reevaluation, the significant change in hematocrit was entirely accounted for by a single outlier. This was attributed to laboratory error.

CONCLUSION

No clinically significant effects on surrogate markers of health were found 6 months after placement of titanium dental implants. This series is the only one in the dental, craniomaxillofacial, and orthopedic literature showing a lack of adverse human health effects after dental implant placement, as measured by accepted surrogate measures of human homeostasis.

Surface analysis of titanium maxillofacial plates and screws retrieved from patients

This investigation is a controlled human plate-retrieval study. The surface appearances and elemental composition of 50 titanium maxillofacial plates and associated screws retrieved from 39 patients were compared with a control sample of unused plates and screws using stereomicroscopy, scanning electron microscopy and energy dispersive X-ray analysis. There were two surface finishes, either anodized or non-anodized. Surface contamination was detected on both retrieved and control plates consisting of aluminium and silica and was more commonly present on non-anodized specimens. Manufacturing defects comprising rough metal edges and protuberances were identified on the unused controls and surgical damage was evident on the retrieved specimens. There were no signs of corrosion or surface deterioration on the retrieved plates and screws which had been in the tissues for between 1 month and 13 years. There was no evidence from this study to support the routine removal of titanium maxillofacial miniplates plates due to corrosion up to a period of 13 years.

Mandibular, sagittal split osteotomies fixed with biodegradable or titanium screws: a prospective, comparative study of postoperative stability

OBJECTIVE

Comparison of skeletal stability following bilateral sagittal split osteotomy (BSSO) advancement of the mandible fixed with titanium or biodegradable bicortical screws.

STUDY DESIGN

Forty consecutive patients underwent mandibular advancement by means of BSSO performed with a standardized technique. In 20 patients rigid fixation was achieved by means of titanium bicortical screws; the other 20 patients were fixed with biodegradable copolymer screws made of poly-L-lactic acid (82%) and polyglycolic acid (18%). Lateral cephalograms were obtained 1 week preoperatively, 1 week postoperatively and after a minimum of 6 months postoperatively. Relevant skeletal points were traced and digitized to evaluate 2-dimensional skeletal change. Changes at each time point were analyzed and compared statistically.

RESULTS

There was no statistically significant difference in long-term stability between the 2 groups. No clinical or radiographic evidence of wound healing problems were noted.

CONCLUSION

Resorbable poly-L-lactic/polyglycolic acid copolymer bicortical screw fixation of a BSSO is a viable alternative to titanium screws for the fixation of advancement BSSO.