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

Reliability and accuracy of the torque applied to osteosynthesis screws by maxillofacial surgeons and residents

Applying the right torque to osteosynthesis screws is important for undisturbed bone healing. This study aimed to compare test-retest and intra-individual reliabilities of the torque applied to 1.5 mm and 2.0 mm osteosynthesis screws by residents and oral and maxillofacial surgeons (OMF-surgeons), to define the reference torque intervals, and to compare reference torque interval compliances. Five experienced OMF-surgeons and 20 residents, 5 of each 4 residency years, were included. Each participant inserted six 1.5 x 4 mm and six 2.0 x 6 mm screws into a preclinical model at two test moments 2 weeks apart (T1 and T2). Participants were blinded for the applied torque. Descriptive statistics, reference intervals, and intra-class correlation coefficients (ICC) were calculated. The OMF-surgeons complied more to the reference intervals (1.5 mm screws: 95% and 2.0 mm screws: 100%) than the residents (82% and 90%, respectively; P = 0.009 and P = 0.007) with the ICCs ranging between 0.85-0.95 and 0.45-0.97, respectively. The residents' accuracy and reliability were inadequate regarding the 1.5 mm screws but both measures improved at T2 for both screw types compared to T1, indicating a learning effect. Training residents and/or verifying the applied torque by experienced OMF-surgeons remains necessary to achieve high accuracy and reliability, particularly for 1.5 mm screws

Biocompatibility and degradation comparisons of four biodegradable copolymeric osteosynthesis systems used in maxillofacial surgery:A goat model with four years follow-up

Applying biodegradable osteosyntheses avoids the disadvantages of titanium osteosyntheses. However, foreign-body reactions remain a major concern and evidence of complete resorption is lacking. This study compared the physico-chemical properties, histological response and radiographs of four copolymeric biodegradable osteosynthesis systems in a goat model with 48-months follow-up. The systems were implanted subperiosteally in both tibia and radius of 12 Dutch White goats. The BioSorb FX [poly(70LLA-co-30DLLA)], Inion CPS [poly([70-78.5]LLA-co-[16-24]DLLA-co-4TMC)], SonicWeld Rx [poly(DLLA)], LactoSorb [poly(82LLA-co-18GA)] systems and a negative control were randomly implanted in each extremity. Samples were assessed at 6-, 12-, 18-, 24-, 36-, and 48-month follow-up. Surface topography was performed using scanning electron microscopy (SEM). Differential scanning calorimetry and gel permeation chromatography were performed on initial and explanted samples. Histological sections were systematically assessed by two blinded researchers using (polarized) light microscopy, SEM and energy-dispersive X-ray analysis. The SonicWeld Rx system was amorphous while the others were semi-crystalline. Foreign-body reactions were not observed during the complete follow-up. The SonicWeld Rx and LactoSorb systems reached bone percentages of negative controls after 18 months while the BioSorb Fx and Inion CPS systems reached these levels after 36 months. The SonicWeld Rx system showed the most predictable degradation profile. All the biodegradable systems were safe to use and well-tolerated (i.e., complete implant replacement by bone, no clinical or histological foreign body reactions, no [sterile] abscess formation, no re-interventions needed), but nanoscale residual polymeric fragments were observed at every system's assessment

Complications of locking and non-locking plate systems in mandibular fractures

This systematic review and meta-analysis was performed to critically assess the methodological quality of the existing systematic reviews, and to evaluate the postoperative complications of the mandibular fractures treated with locking and non-locking plate systems. An electronic search was conducted in PubMed, Embase, Web of Science, Cochrane library's electronic databases and grey literate using a combination of Medical Subject Heading terms and key words, until September 2018. No restrictions were applied to the search strategy. In total, three relevant systematic reviews were included, and the quality of these studies was low. A total of 33 studies (20 randomized studies and 13 non-randomized studies) were included in this systematic review, and 16 of them were included in meta-analysis. Most of the included randomized studies had an unclear risk of bias (Cochrane Collaboration); the quality of non-randomized studies ranged between 6 and 17 (Methodological Index for Non-Randomized Studies MINORS). Based on the results of our meta-analysis, we conclude that locking plates are superior only with respect to the need for mandibulomaxillary fixation (MMF) in the early postoperative period

Histological evaluation of degradable guided bone regeneration membranes prepared from poly(trimethylene carbonate) and biphasic calcium phosphate composites

In oral and maxillofacial surgery, guided bone regeneration using barrier membranes is an important strategy to treat bone defects. The currently used barrier membranes have important disadvantages. Barrier membranes prepared from resorbable poly(trimethylene carbonate) (PTMC) performed as well as collagen barrier membranes. We hypothesized that composite membranes prepared from surface-eroding PTMC and osteoinductive biphasic calcium phosphate (BCP) would enhance bone formation even further. Bicortical critical size defects in the mandibular angle of rats were covered on both sides with the membranes. After 2, 4, and 12 weeks the extent of bone formation in the defects and the soft tissue reaction towards the membranes was examined histologically. At 2 and 4 weeks, the formation of new bone was observed in defects covered with PTMC, PTMC-BCP and Biogide collagen membranes. At 12 weeks, bone defects that were covered with PTMC membranes and control Biogide collagen membranes were fully filled with new formed bone. However, at this time point, defects covered with PTMC-BCP composite membranes had not led to new bone in the defects. Instead a significant tissue reaction, likely to remaining BCP particles, was observed

Quantitative Three-Dimensional Computed Tomography Measurements Provide a Precise Diagnosis of Fractures of the Mandibular Condylar Process

As 2D quantitative measurements are often insufficient, a standardized 3D quantitative measurement method was developed to analyze mandibular condylar fractures, and correlate the results with the mandibular condylar fracture classifications of Loukota and Spiessl and Schroll and clinical parameters. Thirty-two patients with a unilateral mandibular condylar fracture were evaluated using OPT, 2D (CB)CT images, and 3D imaging to measure the extent of the fractures. The maximum mouth opening (MMO) was measured. Ramus height loss could be measured only in OPT, but not in 2D CT images. The Intraclass Correlation Coefficient was excellent in the 3D measurements. In the Loukota classification, condylar neck fractures had the largest median 3D displacement and the highest rotations of the fracture fragments. The largest fracture volume was observed in base fractures. According to the Spiessl and Schroll classification, type V fractures had the largest median 3D displacement and the highest rotation in the X-axis and Z-axis. Type I fractures had the largest fracture volume. We found a moderate negative correlation between MMO and 3D displacement and rotation on Z-axis. The 2D quantitative analysis of condylar fractures is limited, imprecise, and not reproducible, while quantitative 3D measurements provide extensive, precise, objective, and reproducible information