Biomechanical evaluation of plating techniques for fixing mandibular angle fractures: the introduction of a new 3D plate approach

Novel Design of Interlocking 3-Dimensional Miniplate in Mandibular Angle Fractures: An In Vitro Study

The evolution of osteosynthesis has led to the development of novel miniplate designs, including 3-dimensional (3D) miniplates, which offer improved biomechanical stability. However, mandible fractures resulting from the high impact have a complex fracture configuration. Hence, the authors developed interlocking 3D miniplate to overcome the difficulty in miniplate and screw placement to avoid critical anatomic structures, that is, dental roots and nerve, while still providing stability for the fracture fragments. The interlocking 3D miniplates can be formed according to the specific needs by adjusting the horizontal and vertical cross struts configuration. This study describes a design process of interlocking 3D miniplates and evaluates biomechanical performance compared to standard miniplates. Finite element analysis was performed to evaluate the design's stress state using human and goat mandible models under various loading conditions. After the authors, established that our design was feasible for fabrication, the authors developed the prototype for biomechanical testing. Biomechanical testing was conducted on 10 goat mandibles to compare stability and displacement under various load between the interlocking 3D miniplate and the standard miniplate configuration. Biomechanical testing revealed reduced displacement in all directions with the interlocking 3D miniplate compared to the standard miniplate. Furthermore, there was a significant difference in all loads in the buccal-lingual displacement (P<0.05). The novel interlocking 3D miniplate design shows an adequate ability to provide stability for fixation for mandibular fractures, as evidenced by finite element analysis and biomechanical testing. Further research is necessary to validate these findings and explore the clinical application of interlocking 3D miniplates in mandibular fracture management.

Update on ladder plates for mandibular angle fractures

PURPOSE OF REVIEW

Fractures of the mandibular angle are surgically challenging with high rates of postoperative complications. Among established fixation techniques for these injuries, Champy's tension band approach with miniplate fixation has held prominence. Rigid fixation, using two plates, also remains commonly used. More recently, geometric ladder plates, which confer greater three-dimensional stability have been developed to overcome the shortcomings of conventional fixation approaches. Herein, we aim to summarize the recent evidence surrounding the use of ladder plates and offer our own opinion for optimal treatment of these fractures.

RECENT FINDINGS

In high-powered studies, the rates of hardware failure, malocclusion, and malunion are lower among cohorts managed with ladder plates relative to miniplate groups. Rates of infection and paresthesia remain similar. Ladder plates have also been shown to decrease operative time in preliminary study.

SUMMARY

Ladder plates show superiority to miniplate approaches across several outcomes. However, the relatively larger strut plate constructs may not be necessary for minor, uncomplicated fractures. It is our belief that reasonable outcomes may be achieved with either approach depending on surgeon experience and comfort with the given fixation technique.

Assessment of biomechanical properties of specially-designed miniplate patterns in a mandibular subcondylar fracture model with finite element analysis and a servohydraulic testing unit

The aim of our study was to compare the biomechanical stability of three different systems used to fix mandibular condylar fractures on synthetic polyurethane mandibles using a servohydraulic testing unit and finite element analysis (FEA). We measured the resistance to displacement loads causing 1.75 and 3.5mm displacements of the fragments, and the maximum resistance values before failure of the fixation system in 30 condylar necks of 15 polyurethane mandible models. The three subgroups investigated were arranged as a triangular plate (n=10), a quadrangular plate (n=10), and a straight miniplate (n=10). The most successful fixation pattern was achieved with two straight four-hole miniplates. However, the triangular plate can easily be applied as a second option by an endoscopic approach. The rectangular plates showed no success in mandibular condylar fractures.

Three-dimensional versus standard miniplate, lag screws versus miniplates, locking plate versus non-locking miniplates: Management of mandibular fractures, a systematic review and meta-analysis

Background/purpose

The aims of the present study were to 1) evaluate the clinical outcomes between different fixation methods in the management of mandibular fractures (MFs) and 2) determine which fixation method is the best option for the treatment of mandibular fractures.

Materials and methods

A systematic review was conducted according to PRISMA guidelines, examining Medline-Ovid, Embase, and Pubmed databases. Inclusion criteria were studied in humans, including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing the two techniques. In addition, the incidence of complications was evaluated.

Results

Thirty-two publications were included: 20 randomized controlled trials, 4 controlled clinical trials, and 8 retrospective studies. There were statistically significant advantages for 3-dimensional miniplate and lag screws. There was no statistically significant difference between locking plates and standard miniplates (P = 0 0.2). The cumulative odds ratio was 0.64, meaning that the use of locking miniplate in the fixation of MFs decreases the risk for postoperative complications by 36% over the use of standard miniplates.

Conclusion

The results of the three-Dimensional Versus Standard miniplate showed that 3-dimensional miniplate is the best option for mandibular fractures. Regarding Lag Screws Versus Miniplates results of the meta-analysis found that the use of lag screws is superior to using miniplates in reducing the incidence of postoperative complications. And in regards to locking miniplates versus non-locking miniplate, the analysis indicates that the 2.0-mm locking miniplate is a prospective fixation system in the treatment of maxillofacial fractures.

Three-Dimensional Finite Element Analysis of Different Plating Techniques for Unfavorable Mandibular Angle Fractures

The purpose of the current study was to assess the biomechanical behavior of 5 different fixation schemes for unfavorable mandibular angle fractures using the three-dimensional finite element analysis method. Five different miniplate fixation schemes were modeled for the fixation of unfavorable mandibular angle fractures. A double parallel miniplate (M1), which was placed at the halfway point of the mandibular angle height; a 1/3 superior-positioned miniplate (M2); a single miniplate (M3), which was placed at the halfway point of the mandibular angle height (1/2 middle-positioned); a 1/3 inferior-positioned miniplate (M4); and an X-miniplate which was placed at the halfway point of the mandibular angle height (M5). The lowest mechanical stresses were detected in the double miniplate model when compared with the other schemes, whereas 1/3 inferior-positioned miniplate had the highest stress and displacement values. The authors suggest that the double miniplate is an adequate rigid fixation technique, whereas the 1/3 inferior-positioned miniplate configuration should not be used in case of unfavorable mandibular angle fracture.

Three dimensional versus standard miniplate fixation in the management of mandibular fractures: A meta-analysis of randomized controlled trials

The aim of this meta-analysis is to evaluate the efficacy of the 3-dimensional miniplate system in comparison with the standard miniplate system for the treatment of mandibular fractures (MFs). A systematic review was conducted according to PRISMA guidelines, examining Medline-Ovid, Embase, and PubMed databases. The primary search objective was to identify all papers reporting the results of randomized control trials (RCTs) for the treatment of adults with mandibular fractures, with the aim of comparing the different techniques. The incidence of complications was evaluated; nine studies including 283 patients with different fracture sites were enrolled in the analysis. The results showed no significant differences in overall complications (odds ratio [OR], 0.92; 95% confidence interval [CI], 0.552-1.542; P = 0.81), postoperative infections (OR, 0.99; 95% CI, 0.40-2.48; P = 0.89), wound dehiscence (OR, 0.96; 95% CI, 0.13-7.37; P = 0.96), paresthesia (OR, 0.47; 95% CI, 0.20-1.07; P = 0.11), or malocclusion (OR, 1.8; 95% CI, 0.39-8.32; P = 0.47) between standard miniplates and 3-dimensional miniplates for treating mandibular fractures. Mandibular fractures treated with 3-dimensional miniplates and standard miniplates presented similar short-term complication rates, and the low postoperative maxillomandibular fixation rate of using standard miniplates also indicated that the standard miniplate has a promising application in the treatment of mandibular fractures.

Treatment of Mandibular Angle Fractures with Single Three-Dimensional Locking Miniplates without Maxillomandibular Fixation: How Much Fixation Is Required?

The aim of this simple nonrandomized and observational study was to evaluate the efficacy of single three-dimensional (3D) plate for the treatment of mandibular angle fractures without maxillomandibular fixation. A total of 30 patients with noncomminuted fractures of mandibular angle requiring open reduction and internal fixation were included in the study. All the patients were treated by open reduction and internal fixation using single 3D titanium locking miniplate placed with the help of transbuccal trocar or Synthes 90-degree hand piece and screw driver. 3D locking titanium miniplates used in our study was four-holed, box-shaped plate, and screws with 2 mm diameter and 8 mm length. The following clinical parameters were assessed for each patient at each follow-up visit: pain (visual analog scale: 0-5), swelling (visual analog scale: 0-5), mouth opening, infection, paresthesia, hardware failure (plate fracture), occlusal discrepancies, and mobility between fracture fragments. A significant decrease in pain level was seen during the follow-up visits. No statistically significant changes were seen in swelling, but mouth opening increased in the subsequent visits. Also better results were seen in terms of fracture stability and occlusion in the postoperative period. Two cases of infection and two cases of hardware failure were noted in sixth postoperative week. 3D plating system is an easy to use alternative to conventional miniplates to treat mandibular angle fractures that uses lesser foreign material, thus reducing the operative time and overall cost of the treatment. Better fracture stability and occlusion was also achieved using the 3D plating system.

Biomechanical Evaluation of Different Plating Methods Used in Mandibular Angle Fractures With 3-Dimensional Finite Element Analysis: Favorable Fractures

PURPOSE

The aim of the present study was to evaluate the performances of 5 different plating techniques for fixation of favorable mandibular angle fractures using the 3-dimensional finite element analysis (FEA) method.

MATERIALS AND METHODS

Five different miniplate placement configurations were considered for the fixation of favorable mandibular angle fractures. The following models were created: a double parallel miniplate (M1) placed at the halfway point of the mandibular angle height; a one-third superior-positioned miniplate (M2); a single miniplate (M3) placed at the halfway point of the mandibular angle height (one-half middle-positioned); a one-third inferior-positioned miniplate (M4); and an X-shape miniplate (M5).

RESULTS

The M1 and M4 miniplates showed the lowest mechanical stress compared with the other configurations, whereas the M3 and M5 miniplates showed the highest stress levels.

CONCLUSION

For favorable mandibular angle fractures, the authors suggest the M1 miniplate or, if used alone, the M4 miniplate is adequate for rigid fixation.

In vitro evaluation of the resistance of three types of fixation to treat fractures of the mandibular angle

The purpose of this study was to compare the mechanical resistance of three different plates used to treat fractures of the mandibular angle: a regular 4-hole plate, a longer 4-hole plate (both positioned using the Champy technique), and a 3-dimensional plate positioned over the oblique line. Three equal groups of replicas of human dentate mandibles made out of polyurethane resin were used (n=21 in each group). The force was applied perpendicular to the occlusal plane at a rate of 2mm/minute at three different points: the first molar on the sectioned side; the first molar on the contralateral side; and between the central incisors. This was followed by a resistance-to-load test. The two varying factors (type of plate and site-of-load application) were tested by analysis of variance, and probabilities of less than 0.05 were accepted as significant. There were no significant differences between the subgroups, or between the mean values of the different types of plates (p=0.925). The three types of plates showed similar mechanical behaviour, which showed that the 3-dimensional plates positioned over the oblique line can produce mechanical scores similar to those of conventional plates.

Evaluation of Three Different Osteosynthesis Methods for Mandibular Angle Fractures: Vertical Load Test

The aim of this study was to evaluate the mechanical behavior of different rigid fixation methods in mandible angle fractures. Three different plates were tested: one 4-hole grid miniplate, one 8-hole curved grid miniplate, and one 4-hole straight miniplate.For the loading tests, 30 polyurethane hemimandibles sectioned at the angle area to simulate a simple angle fracture were used: 10 hemimandibles for each group. The mechanical evaluation revealed that the straight plate positioned at the tension zone presented the best results in supporting vertical loading in the predefined displacement moments of 1, 3, and 5 mm. Regarding the grid plates, there was no statistically significant difference between the smaller and the larger plate.According to this sample, the straight plate positioned in the tension zone presented better results than the other 2 different grid plates positioned at the neutral zone.

Three dimensional versus standard miniplate fixation in management of mandibular fractures: A systematic review and meta-analysis

PURPOSE

The aims of the present study were to 1) evaluate clinical outcomes between standard and three-dimensional (3D) miniplate fixation in the management of mandibular fractures and 2) determine which fixation method is the best option for the treatment of mandibular fractures.

MATERIALS AND METHODS

A comprehensive electronic search language without date was performed in July 2015. Inclusion criteria were studies in humans, including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing the two techniques. In addition, the incidence of complications was evaluated.

RESULTS

Seventeen publications were included: nine randomized controlled trials, three controlled clinical trials, and five retrospective studies. The meta-analyses showed statistically significant differences for the incidence of hardware failure, malocclusion, and postoperative trismus. There were no significant differences in the incidence of postoperative infection, wound dehiscence, non-union/malunion, and paresthesia. The cumulative odds ratio was 0.48, meaning that the use of 3D miniplates in the fixation of mandibular fractures decreases the risk of the event (postoperative complication) by 52%.

CONCLUSION

The results of this meta-analysis showed that the use of 3D miniplates was superior to the two-miniplate technique in reducing the incidence of postoperative complications in the management of mandibular fractures.

Biomechanical comparison of four mandibular angle fracture fixation techniques

The aim of this study was to make a comparison of the biomechanical behavior of four different internal fixation systems for mandibular angle fractures. A total of 40 polyurethane mandible replicas were employed with different fixation methods: group 1SP, one 2.0-mm four-hole miniplate; group 2PPL, two 2.0-mm four-hole parallel miniplates; group 3DP, one 3D 2.0-mm four-hole miniplate; and group 3DPP, one 3D 2.0-mm eight-hole miniplate. Each group was subjected to incisal or homolateral molar region loading. The load resistance values were measured at load application causing tip displacement of 1, 3, and 5 mm, and at the time at which the system achieves its maximum strength (MS). Means and standard deviations were compared among groups using analysis of variance and the Tukey test. Group 2PPL showed higher strength for all the displacements. For incisal loading, no statistically significant differences were found between groups 1SP, 3DP, and 3DPP. For molar loading, group 1SP and 3DPP showed statistically significant differences. For MS testing, group 1SP and 2PPL showed statistically significant differences in incisal loading; group 1SP and 3DP showed no statistically significant differences; and group 3DPP showed lower values of strength. Two parallel miniplates provide the most favorable mechanical behavior under the conditions tested.

Fixation of mandibular angle fractures: clinical studies

PURPOSE

The purpose of this study was to review the literature regarding the evolution of current thoughts on fixation of mandibular angle fractures (MAFs).

METHODS

An electronic search in PubMed was undertaken in August 2012. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included studies from the last 30 years (from 1983 onwards) reporting clinical studies of MAFs.

RESULTS

The search strategy initially identified 767 studies. The references from 1983 onwards totaled 727 articles. Fifty-four studies were identified without repetition within the selection criteria. Two articles showing significance in the development of treatment techniques were included. Additional hand-searching yielded 13 additional papers. Thus, a total of 69 studies were included.

CONCLUSIONS

Prospective randomized controlled studies of MAFs repair techniques are scarce. The available data at best predict that complications are associated with all kinds of fixation techniques. The similar results of complications in studies using different methods of fixation indicate that biomechanics are only one factor to be considered when treating MAFs. A second fracture in the mandible (which was observed in the majority of the studies' population) can confound the outcome data because the fixation requirements of a double fracture are often different from those for an isolated fracture. It can be necessary additional effort intended for increase of stability when using biodegradable plate system to fixate MAFs. The use of 1.3 mm malleable miniplates was associated with an unacceptable incidence of plate fracture, suggesting that this is not the most adequate system to treat MAFs. The use of the 3D grid plates has shown good clinical results. The efficiency of locking miniplate system is yet to be proven because there are few clinical studies with its use to fixate MAFs, although they have shown good results. When considering the use of semirigid or rigid fixation systems, the use of two miniplates outweigh the advantages of the use of one reconstruction plate, although the use of miniplates is not recommended for displaced comminuted MAFs. Although it has been shown that absolute rigid fixation is not necessary for fracture healing, any system that provides superior stability without impacting negatively on other aspects of the procedure, i.e., time, exposure, and cost, should be favored. MAFs can be treated in a highly effective way and with a relatively low rate of complications with monocortical miniplate fixation. The large number of studies on the treatment of MAF reflects the fact that a consensus has not been reached for a single, ideal treatment method.

Biomechanical strength analysis of mini anchors for the temporomandibular joint

INTRODUCTION

The usage of mini anchors for the treatment of internal derangements of the temporomandibular joint (TMJ) is considered an innovative treatment, and it has presented excellent clinical results in the stabilization of the articular disc. This study aimed to evaluate, through mechanical tensile testing, the resistance of mini anchors for TMJ articular disc repositioning.

MATERIALS AND METHODS

Ten thermoplastic polymer poly-ether-ether-ketone (PEEK) mini anchors were tested in artificial polyurethane blocks with a pullout test in a mechanical Instron™ machine, model 4411. The mini anchors were pulled out until failure and the force and displacement were recorded for each specimen. A small standard deviation was noted, which indicated reproducibility.

RESULTS

The findings indicate that Cillen™ mini anchors presented a mean force at failure up to 46.1 N with similar values in the scientific literature. Nevertheless, further studies should be conducted for a comparison of PEEK mini anchors with other commercially available anchors, in addition to studies related to PEEK, a scarcely known material in the dentistry field.

Fixation of mandibular angle fractures: in vitro biomechanical assessments and computer-based studies

PURPOSE

The purpose of this study was to review the literature regarding the evolution of current thoughts on fixation of mandibular angle fractures (MAFs), based on in vitro biomechanical assessments and computer-based studies.

METHODS

An electronic search in PubMed was undertaken in August 2012. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included studies from the last 30 years (from 1983 onwards).

RESULTS

The search strategy initially identified 767 studies. Thirty-one studies were identified without repetition within the selection criteria. Two articles showing significance in the development of treatment techniques was included. Additional hand searching yielded five additional papers. Thus, a total of 38 studies were included.

CONCLUSIONS

The osteosynthesis positions as well as the plating technique play important roles in the stability of MAF repair. The only in vitro study evaluating the use of wire osteosynthesis concluded that wires placed through the lower border approach would provide greater stability than those at the upper border. Many studies indicate that the use of two miniplates avoids (or decreases) lateral displacement of the lower mandibular border and opening of the inferior fracture gap. Some studies even suggest that the use of two miniplates may be considered a more "rigid" fixation technique for MAFs than the use of a reconstruction plate. When using two miniplates, the biplanar plate orientation provides greater biomechanical stability than the monoplanar one. However, despite its greater biomechanical stability, the two-miniplate technique has some disadvantages that should also be taken into account. Studies with biodegradable plates suggest the use of at least two plates for each MAF. There are few studies with compression plates, and they have not yet reached a consensus. The solitary lag screw proved to withstand the functional loading of the mandible; however, only few biomechanical assessments were performed. In vitro studies have shown good biomechanical stability with the use of 3-D grid plates. The use of malleable miniplates alone is not sufficient to withstand the early postoperative bite force. Some studies suggest that the segment of the tension band miniplate located at the distal fragment of the MAF should be fixed with three screws. The studies also showed some limitations. None considered the stabilization of the fracture site afforded by the masseter-pterygoid muscle pouch. Most of the studies did not evaluate plating system strength in the long term and therefore did not observe the effect of resorption on the strength of the different biodegradable plating systems. Another limitation of many studies is the absence of a control group. A confounding factor that could not be tested in in vitro investigations is the additional resistance to displacement of jagged fracture margins present in the human fracture.