art4_2021_2

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                    MAXILLOFACIAL SURGERY
                    OSTEOSYNTHESIS MATERIALS IN MAXILLOFACIAL
Review Articles
                    SURGERY: REJECTION, REMOVAL, CORROSION AND
                    PARTICLE DETECTION RATES
                    Samy El Bachaoui1a           , Constantinus Politis1b*

                    1Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Leuven, Leuven, Belgium

                    MD, Master’s Student in Medicine; e-mail: samy.elbachaoui@gmail.com; ORCIDiD: https://orcid.org/0000-0003-4492-7564
                    a

                    MD, DDS, MM, MHA, PhD, Professor & Chairperson; e-mail: constantinus.politis@uzleuven.be; ORCIDiD: https://orcid.org/0000-0003-4772-9897
                    b



                    ABSTRACT                                                                            https://doi.org/10.25241/stomaeduj.2020.8(2).art.4

                    Background Titanium is traditionally the material of choice for osteosynthesis in maxillofacial surgery and
                    has a wide array of application in this field. Conversely, a growing interest for alternative fixation methods
                    has emerged in the literature. Promising results have been reported for 3D-designed and manufactured
                    (CAD/CAM) titanium materials, whereas the use of biodegradable materials seems to be a more controversial
                    topic.
                    Objective To conduct a narrative review on the complications related to osteosynthesis materials in
                    maxillofacial surgery in terms of rejection-, removal-, corrosion- and particle detection rates.
                    Data Sources A literature search was performed in April 2020 using the electronic database PubMed
                    (National Library of Medicine, NCBI). The search included studies published between 1999 and March 2019.
                    Study Selection Articles were eligible for inclusion when data for the outcomes of interest were available.
                    Data Extraction Complication rates including rejection-, removal-, corrosion- and particle detection rates
                    were extracted.
                    Data Synthesis The data were synthesized and analyzed according to the different types of osteosynthesis
                    materials and fixation methods. Finally, the results were summarized and recommendations were listed for
                    different types of surgical indications.

                    KEYWORDS
                    Mandibular Reconstruction; Bone Plates; Postoperative Complications; Surgical Wound Dehiscence; Corrosion.

                    1. INTRODUCTION                                                                 material [4,5]. Several studies have analyzed these
                                                                                                    different types of materials in detail, proving each
                    The use of plates and screws for osteosynthesis is                              material has its own advantages and disadvantages.
                    the golden standard in maxillofacial surgery. In the                            However, an overview comparing the complication
                    literature, a wide range of different types of materials                        rates of the different material types is lacking. The
                    are used for different purposes, and each type of                               aim of this narrative review was to compare the
                    material has its own properties. Stainless steel was                            complication rates related to osteosynthesis
                    the first type of material to dominate the market, but                          materials and reconstruction plates in terms of
                    it has been left behind due to its toxic and corrosive                          rejection, removal, corrosion and particle detection
                    properties [1]. Stainless steel was replaced by tita-                           in soft tissues.
                    nium as the golden standard for osteosynthesis,
                    which was found to be much more efficient, because                              2. MATERIALS AND METHODS
                    of its non-toxicity and corrosion-resistance [1]. Since
                    the introduction of titanium, an important evolution                            PubMed was searched for articles that compared
                    has been witnessed from standard titanium plates                                the different outcomes of interest from human
                    and screws to 3D -designed and -manufactured                                    results concerning osteosynthesis material and
                    (CAD/CAM) titanium plates and screws [2,3]. Other                               reconstruction plates. A lot of different outcomes
                    contenders in this field are the bioresorbable                                  are described in the literature, and not all authors
                    materials, which in theory are interesting because                              use the same terminology. The term ‘rejection’ could
                    of their bioresorbable aspects and the possibility to                           not be found as such in the database, therefore it
                    avoid a second surgery to remove the osteosynthesis                             was redefined as a collective term for different more
                                  OPEN ACCESS This is an Open Access article under the CC BY-NC 4.0 license.
                                  Peer-Reviewed Article
                        Citation: El Bachaoui S, Politis C. Osteosynthesis materials in maxillofacial surgery: rejection, removal, corrosion and particle detection rates.
                        Stoma Edu J. 2021;8(2):114-119
                        Received: February 20, 2021; Revised: February 28, 2021; Accepted: March 08, 2021; Published: March 20, 2021
                        *Corresponding author: Prof. Dr. Constantinus Politis, MD, DDS, MHA, MM, PhD, Department of Oral and Maxillofacial Surgery, University Hospitals
                        Leuven, Kapucijnenvoer 33, Leuven, BE-3000 Belgium
                        Tel/Fax: +32 16 33 24 62; e-mail: constantinus.politis@uzleuven.be
                        Copyright: © 2021 the Editorial Council for the Stomatology Edu Journal.




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                                                            2.1.2. Exclusion Criteria




                                                                                                                      Review Articles
                                                            m Search A:
                                                            - Population: N < 100
                                                            - Publication dates older than the past 10 years
                                                            - Study type: case reports, expert opinions, animal
                                                            studies, ex vivo experiments
                                                            m Search B:
                                                            - Study type: case reports, expert opinions, animal
                                                            studies, ex vivo experiments

                                                            3. RESULTS

                                                            3.1. Rejection- and Removal Rates
                                                            3.1.1. Titanium Materials
                                                            3.1.1.1. Miniplates vs Reconstruction Plates
                                                            2 studies were found that compared these fixation
                                                            systems. One systematic review included 5 studies
Figure 1. Flowchart of the study selection process.         with 511 cases who underwent vascularized osteo-
                                                            cutaneous flap reconstruction of the mandible [6].
commonly used outcomes in the literature such as            Patients with miniplates had a slightly higher rate of
‘infection’, ‘wound dehiscence’, ‘plate exposure’, or       complications than did cases using reconstruction
‘screw loosening’. The search was split into 2 parts:       plates (RR = 1.1), but no significant difference in
the outcomes of ‘rejection’ and ‘removal’ were              complication rates was found between the groups.
searched simultaneously (search A), as well as the          The second retrospective study included 682 patients
outcomes of ‘corrosion’ and ‘particle detection’            with fractures of the mandibular symphysis/body [7].
(search B). The main keywords used to build the             Both plating techniques used in this study (1 large
search strategy were: “rejection”, “equipment failure”,     plate vs 2 miniplates) show very good outcomes, but
“infection”, “screw loosening”, “plate extrusion”, “plate   the application of a second bone plate increased the
exposure”, “wound dehiscence”, “device removal”,            incidence of wound dehiscence, plate exposure, and
“plate removal” and “hardware removal” for search           need for plate removal significantly. Overall, a higher
A; “corrosion”, "biocompatible materials/chemistry",        rate of complications was found in the miniplate
"titanium/chemistry", “particle detection”, and             groups. Therefore, one large reconstruction plate
“pigment deposition” for search B (see Appendix I           is recommended above titanium miniplates as a
for full search strategy). An initial review was done       treatment for vascularized osteocutaneous flap
based on title and abstract with a restriction in time      reconstruction of the mandible and for fractures of
of 10 years for search A and no restriction in time for     the mandibular symphysis/body.
search B. Potential articles were then examined in          3.1.1.2. Single Miniplate vs Double Miniplate
full text. A total of 15 studies were included in search    2 studies compared the use of a single- vs a double
A, and three studies in search B (Fig. 1). Articles were    miniplate system in the treatment of a mandibular
eligible for inclusion when data for the outcomes of        angle fracture. Both studies concluded that a single
interest were available. Further restrictions for the       miniplate fixation system resulted in good stability
articles are listed in the exclusion criteria.              and fewer postoperative complications, including
                                                            wound problems/dehiscence, infection, screw
2.1. Selection Criteria                                     loosening, plate fracture and hardware removal [8,9].
2.1.1. Inclusion Criteria                                   3.1.1.3. 2.0 mm Locking Reconstruction Plates
m Search A:                                                 2 studies were included that used 2.0 mm locking
- Population: N >100                                        reconstruction plates for mandibular reconstruction.
- Intervention: the use of osteosynthesis material/         The first study included 307 patients who had
reconstruction plates for any type of maxillofacial         undergone osteocutaneous free flap reconstruction
procedure                                                   with 2.0 mm locking plate fixation following
- Outcome: infection, screw loosening, wound                mandibular resection for benign or malignant
dehiscence, removal of osteosynthesis material/             neoplasia or osteoradionecrosis [10]. Plate removal
reconstruction plates                                       was necessary in 27%, most likely due to surgical
- 10-year time restriction (2010-2020)                      site infection or fistula formation. The second study
- Study type: systematic reviews (and meta-                 included 162 patients with segmental resections
analysis), RCT, experimental controlled studies,            of the mandible reconstructed with angular
observational studies.                                      stable plates [11]. They compared 2.0 mm with 2.5
m Search B:                                                 mm locking reconstruction plates. No significant
- Intervention: the use of osteosynthesis material/         difference in complication rates was reported
reconstruction plates for any type of maxillofacial         between the two types of plates. Plate removal was
procedure                                                   necessary in 28%, which is similar as the findings
- Outcome: corrosion, particle detection in lymph           reported in the first mentioned study.
nodes/soft tissues                                          A total complication rate of 28% was reported,
- Study type: systematic reviews (and meta-                 including loose screws (4.3%), oral- (7.4%) and extra-
analysis), RCT, experimental controlled studies,            oral dehiscences with fistula formation (11.7%).
observational studies.



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                    Dehiscences were seen significantly more often             were 35.9% in the titanium control Group vs 20.7%
Review Articles     in larger defects and with longer plates. Moreover,        in the CAD/CAM custom plates Group. Hardware
                    the rate of dehiscences was significantly higher           removal was necessary in 20.2% of the titanium
                    in the midline. In conclusion, plate removal of 2.0        plates vs 5.6% of the CAD/CAM custom plates.
                    mm locking reconstruction plates is reported to be         CAD/CAM custom plates utilized for rigid fixation
                    around 28%, and the probability of a complication          during microvascular mandibular reconstruction
                    seems to increase with the size of the defect.             demonstrated fewer complications and statistically
                    Therefore, when assessing complication rates, it is        lower reoperation rates when compared with
                    important not only to take the type of osteosynthesis      prebent/preformed titanium plates. The other study
                    material into account, but also anatomic factors such      included was a systematic review and meta-analysis
                    as defect size or anatomic location of the fracture,       including a total of 661 patients in 17 studies that
                    which seem to have a significantly more important          compared 3D miniplates with the standard two-
                    impact on the success rate of the osteosynthesis           miniplate technique in mandibular fractures [2].
                    than the osteosynthesis material itself.                   Mandibular fracture fixation with 3D miniplates
                    3.1.1.4. Locking vs Non-Locking Plates/Screws              was found to decrease the risk of postoperative
                    2 systematic reviews with meta-analysis compared           complications by 52% compared with standard
                    a 2.0 mm locking plate system vs a non-locking             miniplates (OR 0.48). Infection and wound dehiscence
                    system. The double-threaded screws of locking 2.0          were less common in the 3D miniplate Group (OR
                    mm miniplates locking to the bone and the plate            0.58; OR 0.36, respectively), but these findings were
                    create a mini–internal fixator, which results in a         not significant. The cumulative analysis showed a
                    more rigid construction with less distortion of the        statistically significant difference in the outcome of
                    fracture or osteotomy, less screw loosening, and           hardware failure, favoring 3D miniplates (OR 0.14,
                    less interference with bone circulation due to the         p = 0.004). The results of this meta-analysis showed
                    slight pressing of plates against the bone. In short,      that the use of 3D miniplate fixation had lower
                    theoretical advantages of the locking miniplate            complication rates when compared with the use
                    system mainly include less precision required in plate     of standard miniplate fixation in the management
                    adaptation because of the internal/external fixator,       of mandibular fractures. This result was statistically
                    less alteration in osseous or occlusal relationship on     significant. Another interesting outcome measured
                    screw tightening, greater stability across the fracture    in this systematic review was the operative time:
                    sites and less screw loosening [12]. One study found       3D plate technique showed a significant time
                    a cumulative RR of 0.79, meaning the use of the            benefit (p<0.00001). The authors concluded that
                    locking plate in the fixation of mandibular fractures      the major advantage of the 3D miniplate technique
                    decreased the risk of the event (postoperative             is the simultaneous stabilization of the tension and
                    complication) by 21% [13]. However, despite the            compression zones, making the 3D plates a time-
                    theoretical advantages of locking systems, neither         saving alternative to conventional miniplates.
                    of these systematic reviews found a significant            3.1.3. Biodegradable Materials
                    difference in postoperative complication rates             The use of biodegradable materials for osteosynthesis
                    with the use of locking screw/plate systems when           has been an interesting evolution on the market. The
                    compared to the use of non-locking systems in the          theoretical advantage of their resorbable properties
                    management of mandibular fractures.                        sounds promising, as it could resolve the problem of
                    3.1.1.5. Bicortical Screws                                 the need for a second surgery for removal of other
                    One study investigated the use of bicortical lag           non-resorbable materials. However, this feature does
                    screws in 259 patients who had been treated                not tell much about the clinical usefulness of such
                    by either BSSO or bimaxillary-osteotomy, with a            materials, as it does not exclude other complications
                    total of 502 sagittal split osteotomies performed          such as non-union, infection, hardware failure or
                    [14]. Removal of the osteosynthesis material was           removal. One systematic review and three RCT’s
                    necessary in 5.6% of the cases. Bicortical screws had
                                                                               were included in this report. The removal rates varied
                    to be removed at 2.9% of the sites, and 2.3% of the
                    removals were related to infection, including 1.2% of      between 1.5%-16.4% in the titanium control Group
                    intra-oral fistula formation. In conclusion, the authors   and 3.6-26.4% in the biodegradable test Group [5,15].
                    found that rigid fixation with 3 bicortical screws after   The risk of necessity for biodegradable plate and
                    BSSO is reliable with a low rate of postoperative          screws removal was two times higher compared to
                    removal of the osteosynthesis material. Other              titanium plates and screws after long-term follow-up
                    reported incidences indicate a lower rate of removal       >5y (HR 2.0, p = 0.036) [5]. Abscess formation was the
                    of bicortical screws than of miniplates [14]. Bicortical   main reason for plate/screw removal in both groups
                    lag screw fixation was found to be at least as safe        [4,5]. Regarding plate/screws removal after >2 and
                    as miniplate fixation. Moreover, because of better         >5 years follow-up, the performance of the Inion CPS
                    fragment compression, bicortical lag screw fixation        biodegradable system was inferior compared to the
                    offers faster bone healing.
                                                                               KLS Martin titanium system following the fixation
                    3.1.2. 3D (CAD/CAM) Materials
                    2 studies that compared 3D (CAD/CAM) plates and            of mandibular, Le Fort-I, and zygomatic fractures,
                    screws with standard titanium plates and screws            and bilateral sagittal split osteotomies (BSSO) and/
                    were included. One retrospective study included 142        or Le Fort-I osteotomies [4,5]. Given the higher rates
                    subjects who underwent microvascular mandibular            of plate removal, there seems to be no place for the
                    reconstruction [3]. Perioperative complication rates       clinical usage of Inion CPS in treatment of these



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clinical usage of Inion CPS in treatment of these       the presence of titanium particles, as in most similar




                                                                                                                             Review Articles
surgical indications. Another RCT included 200          studies. However, elemental analysis of pigmented
Japanese adults with jaw deformities diagnosed          deposits did not confirm this assumption. The
as mandibular prognathism who underwent BSSO            authors concluded that the incidence of ‘titanium
surgery [16]. The authors found complication rates      deposits’ might have been overestimated in the
of 8.2% in the biodegradable Group and 3.3% in the      past. Moreover, this study did not report any signs
titanium Group, including similar infection rates of    of corrosion of the metal plates. These findings
3.6% and 3.3%, respectively. However, although a        correspond to the results of the third study included,
greater frequency of material-related complication      where no evidence of macroscopic or microscopic
was observed in the biodegradable fixation plate        titanium corrosion or deterioration in the tissues was
Group, no statistically significant differences         found [20]. There was no evidence to support the
were found in the incidence of material-related         view that titanium miniplates should be removed
complications between the biodegradable and             routinely due to corrosion up to a period of 13 years.
titanium groups. The authors suggest that the use of    Overall, these findings suggest that corrosion and
biodegradable plates should be recommended only         particle deposition in surrounding soft tissues are
for minimally loaded situations.                        clinically irrelevant and should not be considered as
                                                        a reason for the removal of titanium osteosynthesis
3.2. Corrosion- and Particle Detection Rates            material on the long-term.
In this second search, the focus was mainly set on
the rates of corrosion and particle detection in soft   4. CONCLUSION
tissues. An extended search was performed for both
outcomes. Data were found reporting titanium            This review provides an overview of the complication
particles detected in animal lymph nodes after          rates related to different types of osteosynthesis
osteosynthesis before [17,18], and several articles     materials and systems used in maxillofacial surgery,
mentioned the detection of titanium particles in        including rejection-, removal-, corrosion- and parti-
locoregional lymph nodes, which are thought to be       cle detection rates in surrounding tissues.
due to the corrosion of the titanium [15]. However,     Reported incidences of removal of titanium fixation
reports of titanium and titanium dioxide in tissues     systems in maxillofacial surgery ranged from 5,6%
adjacent to hardware and in regional lymph nodes        to 28%, depending on the type of titanium fixation
have shown that only clinically insignificant amounts   system and the surgical indication. When comparing
of these materials accumulate [1]. The data analysis    titanium- to 3D (CAD/CAM) materials, reported
in this report focusses on the incidence of corrosion   hardware removal rates are up to four times lower
and pigmentation deposits from titanium fixation        for 3D manufactured materials. Moreover, the
systems.                                                use of the 3D miniplate fixation has significantly
Thre studies that examined the outcomes of interest     lower complication rates in the management of
were included. Acero et al. carried out a prospective   mandibular fractures. Therefore, CAD/CAM fixation
histological study on 37 commercially pure titanium     systems are recommended in the management
miniplates, removed from 23 patients who had            of mandibular fractures. Biodegradable materials,
undergone surgery for maxillofacial traumatic           however, are not recommended for clinical usage in
injuries or deformities [18]. Hole-like images were     the treatment of traumatic fractures or osteotomies
found in 35.1% of the plates studied. The authors       in the maxillofacial area, given the higher rates of
suggest that such anomalies may be corrosion effects    plate removal after >5y follow-up.
in a biomaterial, with titanium-particles released to   Finally, corrosion and particle deposition in the
the surrounding tissues. Dark pigmented deposits        surrounding soft tissues seem to be clinically
were found in 80% of the specimens of soft tissue       irrelevant and should not be considered as a reason
surrounding the analyzed plates. Defects on the         for removal of the titanium osteosynthesis material
surface of the biomaterial and pigmented deposits       on the long-term.
in soft tissues surrounding the plates suggest a        CONFLICT OF INTEREST
higher development of corrosion in titanium than        The authors declare no conflict of interest.
previously reported. In a more recent study, 60 pure
                                                        ACKNOWLEDGMENTS
titanium plates retrieved from 44 patients and 60       None.
soft tissue specimens taken from adjacent locations
                                                        AUTHOR CONTRIBUTIONS
were examined [19]. Pigmented deposits were
                                                        SEB: data acquisition, analysis and interpretation of the results,
detected in 68% of the soft tissue specimens. These     author of the article. CP: substantial contribution to the
pigmented deposits were initially also attributed to    conception and design of the study, revision of the manuscript.



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                                                               Appendix I: Pubmed search strategy
Review Articles
                    Search A:
                    ( "Oral Surgical Procedures"[Mesh] OR "Orthognathic Surgical Procedures"[Mesh] OR "Surgery, Oral"[Mesh]
                    OR "Maxillofacial Prosthesis Implantation"[Mesh] OR "Orthognathic Surgery"[Mesh] OR "Facial Bones/
                    surgery"[MAJR] OR "Mandibular Reconstruction"[Mesh]) AND (“Fracture fixation, Internal”[MESH] OR “Fracture
                    fixation*”[TIAB] OR “titanium plate*”[TIAB] OR “Reconstruction plate*”[TIAB] OR “Bone plates”[MESH] OR
                    “Bone plate*”[TIAB] OR “Bone screws”[MESH] OR “Bone screw*”[TIAB] OR “Plate fixation*”[TIAB] OR “Fixation
                    plate*”[TIAB ] OR “osteosynthesis plate*”[TIAB] OR "Bone Plates*/adverse effects"[MAJR] OR “osteosynthesis
                    material*”[TIAB]) AND (“rejection*”[TIAB] OR "Equipment Failure"[MeSHTerms] OR "Infections"[Mesh] OR
                    “Infection*”[TIAB] OR “screw loosening”[TIAB] OR “loosened screws”[TIAB] OR “plate exposure”[TIAB]
                    OR “plate extrusion”[TIAB] OR “wound dehiscence”[TIAB] OR “Device removal”[MESH] OR “Device
                    removal*”[TIAB] OR “plate removal*”[TIAB] OR “Hardware removal”[TIAB]) AND (("randomized
                    controlled trial"[PT] OR “controlled clinical trial”[PT] OR “clinical trial”[PT] OR “comparative study”[PT] OR
                    "Cross-Over Studies"[Mesh] OR "Intervention Studies"[Mesh] OR random*[TIAB] OR controll*[TIAB] OR
                    “intervention study”[TIAB] OR “experimental study”[TIAB] OR “comparative study”[TIAB] OR trial[TIAB] OR
                    evaluat*[TIAB] OR “Before and after”[TIAB] OR “interrupted time series”[TIAB]) NOT ("animals"[MH] NOT
                    (animals[MH] AND "humans"[MH])))

                    Search B:
                    ( "Oral Surgical Procedures"[Mesh] OR "maxillofacial"[TIAB] OR "Orthognathic Surgical Procedures"[Mesh] OR
                    "Surgery, Oral"[Mesh] OR "Maxillofacial Prosthesis Implantation"[Mesh] OR "Orthognathic Surgery"[Mesh]
                    OR "Facial Bones/surgery"[MAJR] OR "Mandibular Reconstruction"[Mesh]) AND ("Fracture fixation, Internal"
                    [MESH] OR "Fracture fixation*"[TIAB] OR "titanium plate*"[TIAB] OR "Reconstruction plate*"[TIAB] OR
                    "Bone plates"[MESH] OR "Bone plate*"[TIAB] OR "Bone screws"[MESH] OR "Bone screw*"[TIAB] OR "Plate
                    fixation*"[TIAB] OR "Fixation plate*"[TIAB ] OR "osteosynthesis plate*"[TIAB] OR "Bone Plates*/adverse
                    effects"[MAJR] OR "osteosynthesis material*"[TIAB]) AND ("Corrosion"[MESH] OR "Corrosion"[TIAB]
                    OR ("Biocompatible Materials/chemistry"[MAJR]) OR "Titanium/chemistry"[MAJR] OR "particle
                    detection"[TIAB] OR "pigment deposition"[TIAB]) AND (("randomized controlled trial"[PT] OR "controlled
                    clinical trial"[PT] OR "clinical trial"[PT] OR "comparative study"[PT] OR "Cross-Over Studies"[Mesh] OR
                    "Intervention Studies"[Mesh] OR random*[TIAB] OR controll*[TIAB] OR "intervention study"[TIAB] OR
                    "experimental study"[TIAB] OR "comparative study"[TIAB] OR trial[TIAB] OR evaluat*[TIAB] OR "Before and
                    after"[TIAB] OR "interrupted time series"[TIAB]) NOT ("animals"[MH] NOT (animals[MH] AND "humans"[MH])))
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                                                                                                                                            Review Articles
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                                                                                      Samy El BACHAOUI
                                                                            MD, Master’s Student in Medicine
                                                                 Department of Oral and Maxillofacial Surgery
                                                                     Faculty of Medicine University of Leuven
                                                                                            Leuven, Belgium
CV
Samy El Bachaoui is a Master’s student in Medicine at the University of Leuven (KU Leuven) with a special interest in Oral- and
Maxillofacial surgery. He obtained his bachelor’s degree in Medicine in 2018 (cum laude), and is expected to obtain his master’s
degree in Medicine in June 2021. He has gained experience with internships in the department of Oral- and Maxillofacial Surgery
at the Geneva University Hospitals and the University Hospitals Leuven under the supervision of Professor Dr. Constantinus
Politis.


Questions
1. What fixation system has the lowest complication rates and is therefore recommended
in the management of mandibular fractures?
qa. Double titanium miniplate system;
qb. Biodegradable materials;
qc. 3D (CAD/CAM) fixation systems;
qd. Locking plates/screws.
2. The risk of postoperative complications is:
qa. Decreased by approximately 50% with 3D miniplates compared to titanium plates in the management
of mandibular fractures;
qb. Three times higher in terms of hardware removal with biodegradable materials compared to titanium
plates;
qc. Significantly lower for double miniplates compared to single miniplates;
qd. Not significantly different for double titanium miniplates compared to a large reconstruction plate in
the management of mandibular fractures.
3. Regarding plate/screws removal after >5 years follow-up following fixation of
traumatic fractures and osteotomies in the maxillofacial area, the performance of the
biodegradable system was assessed as:
qa. Superior compared to the titanium system, therefore the clinical usage of a biodegradable fixation
system in the treatment of these surgical indications is strongly recommended;
qb. Superior compared to the titanium system, therefore the use of biodegradable plates should be
recommended for maximally loaded situations;
qc. Equal compared to the titanium system, therefore the use of biodegradable plates could be a clinically
useful alternative in the treatment of these surgical indications;
qd. Inferior compared to the titanium system, therefore there seems to be no place for the clinical usage of
biodegradable systems in the treatment of these surgical indications.
4. Which of the following statements is true regarding corrosion and/or particle
deposition in surrounding soft tissues?
qa. Corrosion rates of titanium miniplates are clinically relevant and should be considered as a reason for
the removal of titanium osteosynthesis material on the long-term;
qb. Corrosion rates of titanium miniplates are clinically irrelevant and should not be considered as a reason
for the removal of titanium osteosynthesis material on the long-term;
qc. Pigment deposition rates in surrounding soft tissues of titanium plates of up to 90% have been
reported and should therefore be considered as a reason for the removal of titanium osteosynthesis
material on the long-term;
qd. Reports of titanium deposits show no evidence of particle accumulation in tissues adjacent to titanium
hardware nor in regional lymph nodes.


Stoma Edu J. 2021;8(2): 114-119                                                         pISSN 2360-2406; eISSN 2502-0285                     119