The management of mandibular angle fractures remains a subject of ongoing debate in maxillofacial surgery, despite substantial advances in osteosynthesis techniques [15, 16]. Our retrospective two-center study compared the outcomes of single-plate (1P) versus double-plate (2P) fixation for mandibular angle fractures, providing further insights into this controversy.

Based on the classical principles established by Champy et al. [23], fixation with a single superior miniplate along the “ideal line of osteosynthesis” has been advocated for decades. This approach aims to neutralize tensile forces at the superior border, allowing compressive forces to be absorbed by bone contact. Champy’s technique, validated by multiple clinical and experimental studies [3, 24], offers a minimally invasive option with sufficient functional stability for simple, non-comminuted fractures [5].

Our results support the continued application of this principle: although the overall complication rate was higher in the 1P group compared to the 2P group (34.6% vs. 26.8%), the rates of secondary osteosynthesis — representing clinically significant failures — were similar (9.4% vs. 7.6%). While the observed difference in overall complication rates between the two groups reached statistical significance, the absolute difference of 7.8% should be interpreted with caution. Given the retrospective design and the relatively modest margin, the clinical relevance of this finding may be limited. Furthermore, the majority of complications in both groups were managed conservatively and did not result in secondary revision of the osteosynthesis. These results suggest that although statistical significance was achieved—likely influenced by the overall sample size—the clinical impact may be less pronounced. As such, treatment decisions should continue to be guided by patient-specific factors and institutional standards, rather than statistical differences alone.

Previous studies provide mixed evidence. Al-Moraissi and Ellis demonstrated in a comprehensive meta-analysis that single miniplate fixation was associated with fewer postoperative complications compared to double miniplate fixation [14]. Our study does not support these findings, as single-plate fixation was associated with a higher complication rate. On contrary, Danda et al. [35] showed in a randomized clinical trial that the addition of a second plate did not confer a significant advantage in reducing infection rates or improving healing outcomes. Ellis and Walker [24], as well as Schierle et al. [29], also reported higher infection rates in patients treated with two miniplates, suggesting that increased surgical dissection and hardware load might compromise soft tissue healing and predispose to infection. Our results support this statement, and the authors believe that the higher wound infection rate after double-plate fixation can be explained by the extended bone exposure, larger sutured wound and longer duration of surgery. However, while the higher rate of wound infection in the two-plate group may suggest an association with greater surgical exposure and potentially longer operating times, we acknowledge that this interpretation should be made with caution. No intraoperative data on surgical duration or extent of dissection were available for analysis. Moreover, surgical time in teaching hospitals is subject to variation due to the involvement of multiple surgeons with differing levels of experience, which may limit its reliability as a surrogate for tissue trauma or complexity.

Regarding revision surgery, osteomyelitis was the most common reason for secondary osteosynthesis after double-plate fixation (50%). These findings caution against the routine use of two plates in fractures otherwise amenable to single-plate fixation. However, the higher rate of plate/screw loosening after single-plate fixation must be highlighted as a potential shortcoming of this fixation. This may be due to the extensive bony defects in the third molar area, particularly in cases of pathological fractures following third molar removal or after intraoperative third molar removal, which can make the osteosynthesis unstable. As a result, 41.1% of the cases with plate/screw loosening after single-plate fixation needed re-osteosynthesis, which was the most common reason for that (70% among the revision cases). The additional use of an inferior osteosynthesis plate in these cases may be recommended, as it could increase stability. Despite the higher complication rate in the one-plate fixation group, the similar revision rates of both fixation methods reported in this study suggest that single-plate fixation remains an effective and reliable treatment option for most cases, especially when considering the shorter surgical time and the reduced personal and financial resources needed [14, 35].

Among patients with pathological fractures involving bony defects in the third molar region, we observed a higher complication rate in the 2-plate group (35.0%) compared to the 1-plate group (18.8%). While plate/screw loosening was more frequent in the 2-plate group, the proportion of cases requiring secondary osteosynthesis remained similar (10.0% vs. 6.3%). These findings do not clearly support the assumption that dual plating improves mechanical stability in compromised bone scenarios. On the contrary, increased hardware may contribute to greater mechanical strain or early loosening. Given the small sample size, these observations should be interpreted with caution, and further prospective studies are needed to explore these trends more conclusively.

Our findings confirm observations made by Steffen et al. [17], who emphasized that deviations from AO principles, as well as patient-related factors such as smoking and systemic disease, significantly contribute to surgical failures requiring secondary interventions. Additionally, we found that patients with a longer duration of postoperative IMF were significantly associated with a higher risk of postoperative complications and secondary osteosynthesis. However, this finding needs to be carefully interpreted. We believe that it is not the postoperative IMF that may lead to a wound infection, but rather a perioperative wound infection, a demanding osteosynthesis or even patient noncompliance may tendent to prolong the duration of postoperative IMF.

Biomechanical studies by Squier et al. [3] confirmed that while superior border fixation offers sufficient load-sharing under controlled conditions, dual plating may improve resistance against vertical forces. However, whether this mechanical advantage translates into superior clinical outcomes remains debatable, especially when considering the increased risk of morbidity associated with more extensive surgical interventions. In this study, there was no significant difference in the rate of postoperative occlusal disorders between the two methods of fixation. However, six out of nine cases with postoperative occlusal disorder at both clinics required revision of the osteosynthesis. Whether the occlusal disorder was detected directly postoperatively or was developed over time remains unknown and needs to be investigated in future studies to determine whether the cause was inadequate intraoperative repositioning or developed from postoperative biomechanical instability.

In addition to standard plating, three-dimensional (3D) miniplates have been developed to simultaneously stabilize both tension and compression zones [5, 8, 15]. Meta-analyses by Wusiman et al. [5, 15] suggested that 3D plates could reduce hardware failure, malunion, and overall complication rates compared to standard two-dimensional plates. Nevertheless, systematic reviews such as that by Kotha et al. [25] emphasized that 3D plates do not consistently outperform single-plate fixation in simple fracture patterns, and their advantages are more pronounced in complex fractures.

The management of third molars (M3) in the fracture line remains another important consideration. In our cohort, the presence of impacted third molars significantly increased the risk of postoperative complications. This observation aligns with findings by Gong et al. [11], who reported that impacted third molars increase the likelihood of unfavourable fracture patterns and delayed healing. In contrast, Sexton et al. [9] suggested that routine removal of third molars may not be necessary unless they directly interfere with fracture reduction or increase infection risk. Other studies, including those by Zanakis et al. [37] and Edouma et al. (50), suggested that retained third molars do not necessarily impair fracture healing, emphasizing the need for individualized decision-making. Rivera-Herrera et al. [38] stressed the importance of thorough radiographic evaluation (e.g., Winter and Pell-Gregory classifications) to better predict potential complications.

Despite ongoing technological advances, including the use of CAD/CAM-designed osteosynthesis plates [30] and finite element analysis (FEA)-validated designs (32, 76), the Cochrane review concluded that no single fixation method has demonstrated superiority across all clinical scenarios [16]. Therefore, a patient-specific, individualized treatment approach remains the gold standard [16, 17], taking into account fracture characteristics, systemic risk factors such as smoking and diabetes, and surgeon expertise (87).

Finally, recent innovations, such as newly designed miniplates introduced by Gamit et al. [10], show promising results in terms of improved bite force restoration. However, widespread adoption of these new technologies requires further validation through large-scale, prospective randomized studies.

A key strength of this study is the relatively large sample size, encompassing 253 patients with 264 mandibular angle fractures treated across two specialized oral and maxillofacial surgery centers over a ten-year period. The strict inclusion and exclusion criteria, consistent intraoral surgical approach, and detailed multivariable analysis of patient-, trauma-, and procedure-specific factors enhance the validity and clinical relevance of our findings. Furthermore, the comparison of two standardized osteosynthesis protocols—single-plate versus double-plate fixation—within distinct institutional frameworks provides valuable real-world insights into current surgical practice.

However, certain limitations must be acknowledged. Firstly, the retrospective design inherently introduces potential selection and information bias. Second, the non-randomized design, in which each participating center adhered to a distinct and exclusive fixation protocol. As a result, potential center-specific differences—such as variations in surgeon expertise, perioperative care, postoperative follow-up durations, and institutional practices—may have influenced the outcomes independently of the fixation technique itself. Therefore, the results should be interpreted as a comparison of institutional treatment protocols, rather than an isolated evaluation of fixation methods. While both approaches were standardized within each center, we acknowledge that this design inherently introduces a risk of center bias. Third, the statistically significant difference in complication rates must be interpreted cautiously, as the absolute difference was small and may not translate into meaningful clinical impact. Also, the lack of intraoperative data such as surgical duration or extent of dissection may prevent definitive conclusions about the cause of higher wound infection rates in the two-plate group. Additionally, in teaching hospital settings, surgical time may be influenced by varying surgeon experience and training and thus may not reliably reflect procedural complexity. Furthermore, some of the observed differences in complication rates may be influenced by institutional protocols rather than the fixation method alone. For example, clinic B routinely performed intraoperative CBCT imaging to verify reduction and fixation and used continuous sutures with finer material (Vicryl 4 − 0), whereas clinic A used postoperative OPGs and interrupted sutures (Vicryl 3 − 0). These differences in perioperative workflow, imaging, and soft tissue management could have contributed to outcome variation and represent potential center-specific confounders beyond the plate configuration. Fourth, since extraoral approaches have been excluded, the indication criteria may have been varied between the two clinical centers. The differences between the centers in using postoperative IMF may also had a contribution to the possible outcomes. Fifth, biomechanical assessments were inferred from existing literature rather than directly evaluated through in vivo analysis or finite element modelling. Since postoperative IMF was applied in most cases at both centers, no conclusion can be drawn about the adequacy of load-sharing between the two fixation methods without postoperative IMF. Sixth, this study did not examine the quality of repositioning in terms of fracture accuracy and occlusal precision, which could also impact our surgical outcomes. Consequently, the study lacks also clinical interpretation of the observed deviations in terms of long-term clinical and functional outcomes. Prospective research with 1-year follow-up assessment is needed to correlate the repositioning results with long-term clinical and functional outcomes such as malocclusion, maximum interincisal opening, TMJ mobility/dysfunction, or masticatory performance. Seventh, some significant predictors of secondary osteosynthesis, such as diabetes mellitus, were based on very small subgroups and may lack statistical robustness. Thus, the study may be underpowered to detect reliable associations for infrequent conditions such as diabetes and these findings should be interpreted with caution. Furthermore, while multivariate analysis adjusted for known confounders, unmeasured variables may still impact postoperative outcomes.

Future prospective randomized controlled trials and standardized biomechanical studies are warranted to validate and expand upon these findings.

The increased rate of plate/screw loosening after single-plate fixation may be attributed to insufficient stability in cases with substantial bony defects in the third molar region—particularly in pathological fractures or following intraoperative third molar removal. In such scenarios, the addition of an inferior plate may enhance mechanical support and reduce the need for secondary osteosynthesis. However, although the overall complication rate was higher in the one-plate group, the rate of revision surgery was comparable, suggesting that the presumed biomechanical advantage of dual plating in M3-related defects remains unproven based on our data.

Conversely, the higher incidence of wound infection and osteomyelitis following double-plate fixation suggests that increased hardware and soft tissue manipulation may elevate the risk of postoperative complications. While extended antibiotic therapy and short-term drainage might reduce this risk, such measures must be critically weighed against current clinical guidelines advocating perioperative prophylaxis only.