Electromyographic Study of Facial Nerve Function Using Two Different Surgical Approaches in Low Condylar Fractures of the Mandible: A Randomized Controlled Clinical Trial.

BACKGROUND: Facial nerve (FN) dysfunction is a potential complication during open reduction of mandibular condylar fractures. PURPOSE: The purpose of this study was to measure and compare the postoperative FN function following transparotid (TP) and transmasseteric anterior parotid (TMAP) operative approaches in open reduction and internal fixation of condylar fractures using electromyogram. STUDY DESIGN, SETTING, SAMPLE: A randomized controlled clinical trial was designed. The study was conducted in a single tertiary-care hospital in the inpatient setting. Patients aged above 18 years with unilateral condylar fracture of the jaw or bilateral condylar fractures undergoing surgery on only 1 side were included. Patients were excluded if they had fractures of the head, bilateral condylar fractures with surgery planned on both sides, a previous history of surgery in the retromandibular area, existing lacerations to approach condyle, preoperative signs of FN weakness, or a history of parotid surgery. PREDICTOR VARIABLE: The predictor variable was the operative approach and the subjects were allocated randomly to TMAP and TP. MAIN OUTCOME VARIABLE(S): The primary outcome variable was postoperative FN function in the surgical approach employed using the House-Brackmann scale and electromyography (EMG) to record any subtle weakness in nerve function. The FN function is recorded at 3 time intervals postoperatively 1 week (T1), 1 month (T2), and 3 months (T3). The secondary outcomes studied were operating time and any other complications recorded. COVARIATES: Age, sex, fracture pattern with classification of condylar fractures into condylar neck or base fractures according to Loukata et al.4 Any associated fracture of mandible describing the anatomical location viz symphysis and parasymphysis (anterior mandible), body, contralateral condyle or greater than 1 associated fracture were recorded. Similarly, the presence or absence of any associated midface fracture was also recorded to suggest that the study participants were homogenous in all aspects. ANALYSES: Analytical statistics included χ2 test, t-test, and repeated measures ANOVA followed by post hoc test to compare EMG data (mean power and mean amplitude) between 2 operative approaches (TP vs TMAP) for facial muscles including frontalis, oculi, and buccinator at different time intervals (T0, T1, T2, T3). Patients within each group were also analyzed to check for nerve recovery occurring during the follow-up period. The level of significance was set at P < .05. RESULTS: The study sample was composed of 22 patients with a mean age of 32.82 ± 11.21 years in TMAP and 27.82 ± 8.54 years in the TP group respectively (P = .26); male predominance of 81.8 and 90.9% in TMAP and TP group respectively (P = .53) was noted. The FN deficit as assessed by the House-Brackmann scale clinically, was at 54% (T1), 36.4% (T2), and 9.1% (T3) for the TP group and 27% (T1),9% (T2), and 0% (T3) for TMAP group; however, the results were statistically insignificant (P = .31). In surface EMG evaluation, the mean power for the frontalis muscle was significantly higher in the TMAP approach at the T3 time (105.03 ± 9.7 vs 89.56 ± 10; 95% confidence interval -24.28 to -6.65 with P value = .002). TP approach was faster with a mean exposure time of 9.9 minutes. CONCLUSION AND RELEVANCE: The results show that both approaches give comparable long-term results with the TMAP group showing better frontalis muscle activity.

A finite element analysis on the indication for extracting partially impacted mandibular third molars considering mandibular trauma.

BACKGROUND: Patients presenting with partially impacted lower third molars (M3) have a higher likelihood of experiencing angle fractures while simultaneously decreasing the risk of condylar fractures. However, the specific biomechanical mechanism responsible for this occurrence remains unclear. Moreover, there is an ongoing debate regarding whether the removal of M3s might actually increase the risk of condylar fractures. This study aimed to evaluate how the presence of M3s influences mandibular fractures resulting from blows to the symphysis and lateral mandibular body, and to determine the indication for extracting M3s in such cases. METHODS: Models of the mandible with a partially M3-impacted model (M3I), M3-extracted model (M3E), and M3-absent model (M3A) were generated using a computer. A traumatic blown force of 2000 N was applied to the symphysis and the right body of the mandible. Von Mises and principal stresses were analyzed, and failure indexes were determined. Two cases of mandibular linear fractures were chosen for model verification and interpretation. RESULTS: When force was applied to the symphysis, the condylar region exhibited the highest stress levels, while stress in the mandibular angle region was much less regardless of the M3 state. On applying the force to the right mandibular body, stress in the condylar region decreased while stress in the mandibular body increased, especially in the blown regions. Impacted tooth or cavity formation post-M3 extraction led to uneven stress distribution on the blown side of the mandible, increasing the risk of mandibular angle fractures. In cases where M3 was absent or the extraction socket had healed, stress from lateral traumatic blown force was evenly distributed along both the inner and outer oblique lines of the mandible, thereby reducing the risk of mandibular fractures. CONCLUSIONS: The reduced risk of condylar fractures in patients with partially impacted lower M3s and mandibular angle fractures is mainly due to lateral blows on the mandible, which generate less stress in the condylar region than blows on the mandibular symphysis, rather than being caused by the M3 itself. Extraction of the lower M3 can decrease the risk of mandibular fractures, with a minor influence on condylar fractures.

Does the Length of Dental Implants Inserted in Areas of Inferior Alveolar Nerve Lateralization Interfere on Mandibular Resistance to Fracture?

The aim of this study was to compare, in vitro, the mechanical resistance to vertical displacement of the mandible after osteotomy for lateralization of the inferior alveolar nerve and installation of dental implants. One hundred eighty polyurethane mandibles were equally divided into 6 groups: G1-intact hemi-mandibles (control group), G2-hemi-mandibles after osteotomy for lateralization of the inferior alveolar nerve, G3-hemi-mandibles with installation of 3 bicortical dental implants (3.75 × 13 mm), G4-hemi-mandibles with installation of 3 dental implants that did not reach the basal cortical bone (3.75 × 11 mm), G5-hemi-mandibles after osteotomy for lateralization of the inferior alveolar nerve and installation of 3 bicortical dental implants (3.75 × 13 mm) and G6-hemi-mandibles after osteotomy for lateralization of the inferior alveolar nerve and installation of 3 dental implants that did not reach the basal cortical bone (3.75 × 11 mm). The specimens were subjected to linear loading tests. The highest mean value of maximum load was found in G1 (412.36N ±â€Š11.99), followed by G2 (396.87N ±â€Š23.94), G3 (319.63N ±â€Š57.28), G4 (303.34N ±â€Š18.25), G5 (231.75N ±â€Š63.64) and G6 (228.13N ±â€Š20.75). Based on this data, it can be concluded that the bicorticalization (or not) of the implants was not a statistically significant risk factor for the vertical displacement of polyurethane hemi-mandibles.

Treatment of mandibular angle fracture: Revision of the basic principles.

Biodynamics of mandibular angle fractures has been extensively discussed in the literature in search for the best way to fixate and expedite recovery of trauma patients. Pioneers like Michelet and Champy had the greatest impact on evolving of osteosynthesis in maxillofacial traumatology; they introduced their basic principles frequently used to describe the biomechanics of mandibular fixation. Their concept states when a physiologic load is applied on mandibular teeth a negative tension will be created at superior border and a positive pressure will appear at inferior border. These simple definitions are the basis for the advent of fixation modalities in mandibular angle fracture. This article sought to reassess these principals based on load location via finite elements method.

Comparison of two incisions for open reduction and internal fixation of mandibular body fractures: A randomised controlled clinical trial evaluating the surgical outcome.

PURPOSE: The purpose of the study is to compare the surgical access and post-operative outcome of two intra-oral incisions used for approaching a mandibular body fracture. METHODS: This clinical trial involved 60 patients with mandibular body fractures who were randomly allocated to control and study groups. The fractures were approached using the routine vestibular incision in the control group and crevicular incision with vertical release in the study group. The effects of incision design on the post-surgical outcome variables like swelling, trismus, paresthesia, wound healing and gingival recession were statistically analysed with non-parametric tests by using SPSS 22.0 software. Comparison of continuous variables between the groups and time points was done using Mann Whitney test and Friedman test respectively. Chi-square test was used to compare proportions between groups. Dunn's test with Bonferroni correction was used for pair wise comparisons. RESULTS: The study group demonstrated favourable surgical outcome in the immediate postoperative phase as compared to the control group. The difference in mouth opening, swelling and neurosensory impairment between the two groups was found to be statistically significant (p < 0.05). CONCLUSION: Crevicular incision was found to be an ideal alternative to vestibular incision in achieving surgical access and fixation of mandibular body fractures with reduction in postoperative patient discomfort and better surgical outcome.

Is masticatory performance affected after a unilateral condylar fracture? A cross-sectional study.

BACKGROUND: Mandibular fractures, especially condylar fractures, are one of the most common facial fractures. Trauma to this region could possibly compromise masticatory performance, which is a vital function for humans. OBJECTIVE: To objectively determine masticatory performance (Mixing Ability Test; MAT) in patients treated for a unilateral condylar fracture, thereby comparing patients in open and closed treatment groups, and assessing whether there is a positive relationship between this performance and subjective mandibular function (Mandibular Functional Impairment Questionnaire; MFIQ). METHODS: Fifty-eight patients were enrolled in a cross-sectional study and examined on an additional appointment at least 1 year after trauma, during which the patients performed the MAT and completed the MFIQ. The Spearman test was used to assess the correlation between the Mixing Ability Index (MAI) and the MFIQ score. A linear regression was used to explore the effects of different factors on the MAI. RESULTS: The correlation between objective masticatory performance and the subjective mandibular function was positive (r = 0.250; P = 0.033). Better masticatory performance was observed in patients who were male, received physiotherapy, had no other mandibular fractures and/or had satisfactory self-perceived occlusion. No significant difference in the MAI was found between the open and closed treatment groups. CONCLUSION: Independent of the chosen treatment, at least 1 year after treatment, individuals who experienced a unilateral fracture of the mandibular condyle exhibit masticatory capacity comparable with that of individuals who have not suffered such injuries.

An In Vitro Comparison Study of the Use of a Drill or a Saw in the Hunsuck-Dal Pont Modification of the Obwegeser Sagittal Split Osteotomy in Pig Mandibles.

PURPOSE: Fracture lines in unfavorable locations are referred to as "bad splits" in a mandibular sagittal split osteotomy (SSO). Several modifications of the technique by Obwegeser have been introduced to minimize this risk. This in vitro study was performed to determine whether the shape of the osteotomy cut affects the torque and the fracture pattern of an SSO in pig mandibles. MATERIALS AND METHODS: In a split-mouth model, 16 mandibles were split according to the Hunsuck-Dal Pont modification of the Obwegeser technique. Using an oscillating saw, sharp-edged osteotomies were created on one side of the mandible and round-edged osteotomies were created on the contralateral side using a Lindemann bur. Torque forces were measured during the splitting, and the lingual fracture pattern of each split was classified. RESULTS: Torque forces were significantly (P < .05 by paired t test) decreased by 0.77 N-m (15.6%) when a saw was used for the osteotomy. In the 2 groups, fractures were produced along the mandibular canal. The mandible was more often completely fractured, including the lower mandibular border, when the fracture was created with an oscillating saw (P = .06 by Pearson χ2 test). No correlation was found between the torque used and the fracture pattern. CONCLUSION: Compared with round-edged osteotomies, sharp-edged osteotomies in pig mandibles facilitated the Hunsuck-Dal Pont modification of the Obwegeser sagittal splitting procedure and produced predictable results with decreased torque.

Resistance of Mandibular Polyurethane Replicas to Fracture After Removal of Blocks From the Symphysis and Ramus.

BACKGROUND: When block grafts are harvested intraorally, the donor sites may act as stress concentrators and alter the structural integrity of the mandible. PURPOSE: The study aimed to compare displacement and load failure between intact polyurethane mandibular replicas and similar replicas from which blocks were taken at the symphysis or the ramus. It also aimed to identify trends of load failure. MATERIALS AND METHODS: Thirty-five mandibular replicas were tested to failure with an electromagnetic material testing unit. The variables evaluated in this investigation were maximal load, displacement at maximal load, and fracture location. RESULTS: Statistically significant differences in maximal load were detected between groups (P = 0.0008). Differences between fracture locations were also statistically significant (P < 0.0001). The mandibles from which blocks were removed at the symphysis were significantly more likely to break at a lower maximal load than were the control mandibles (P = 0.0010) or the mandibles from which blocks were removed at the ramus (P = 0.0162). They were also more likely than the control group to break at a lower displacement at maximal load (P = 0.0145). CONCLUSIONS: Location of the donor site significantly influences the structural integrity of mandibular replicas. In addition, the donor site significantly affects the location of mandibular fractures.

Assessment of the Biomechanical Performance of 5 Plating Techniques in Fixation of Mandibular Subcondylar Fracture Using Finite Element Analysis.

PURPOSE: The aim of this study was to compare the performances of 5 plating techniques for fixation of unilateral mandibular subcondylar fracture. MATERIALS AND METHODS: Five titanium plating techniques for fixation of condylar fracture were analyzed using the finite element method. The modeled techniques were 1) 1 straight plate, 2) 2 parallel straight plates, 3) 2 angulated straight plates, 4) 1 trapezoidal plate, and 5) 1 square plate. Three-dimensional models were generated using patient-specific geometry for the mandible obtained from a computerized tomographic image of a healthy living man. Plates were designed and combined with the mandible and analyzed under a 500-N load. RESULTS: The single straight plate presented the most inferior performance; it presented maximum displacement and strain on cortical bone. The trapezoidal plate induced the least amount of strain on cortical bone and was best at resisting displacement. CONCLUSION: The trapezoidal plate is recommended for fixation of subcondylar fracture.

Comparison of Different Fixation Types Used in Unilateral Mandibular Condylar Fractures: An In Vivo Study With New Biomechanical Model.

INTRODUCTION: The aim of this in vivo study is to compare the single-titanium, double-titanium mini plate, and single resorbable plate systems used in internal rigid fixation of the unilateral mandibular condylar fractures on new design biomechanical model. METHODS: Thirty synthetic polyurethane models were used for biomechanical testing. Fracture lines were created for each model. Fragments were fixed with single-titanium plates in Group A (n = 10), double-titanium plates in Group B (n = 10), and single biodegradable plate (PPLA) in Group C (n = 10). Masticatory forces were applied to the models and the biomechanical properties of the titanium plate and screws, resorbable plate, and screws were evaluated. RESULTS: The average failure force for Group A, Group B, and Group C is 199, 324, 177N and the average bone displacement for Group A, Group B, Group C is 1.9, 0.3, 2.1 mm, respectively. DISCUSSION: Double titanium plates showed the most acceptable results in the fixation of unilateral subcondylar fractures where the single titanium and biodegradable plate systems failed to provide enough stability in unilateral subcondylar fracture fixation. Biodegradable plate systems are still not an alternative in fixation of unilateral condylar fractures.

Does Soft Tissue Injury Affect Intracapsular Condylar Fracture Healing?

PURPOSE: The soft tissue healing patterns of mandibular intracapsular condylar fracture (ICF) after closed treatment have not been well characterized. The purpose of the present study was to classify the injury and healing patterns in adult patients using magnetic resonance imaging (MRI) evaluation. PATIENTS AND METHODS: The present study represents a retrospective review of MRI examinations performed on patients treated with closed reduction of an ICF from 2010 to 2013. The MRI scans used for comparison were taken at 1 week and at least 3 months after the injury. These studies were used to identify the common patterns of hard and soft tissue derangements. The predictor variable was the type of soft tissue injuries, categorized as anteromedial displacement of both the disc and the fractured bony fragment, anteromedial displacement of the bony fragment with the disc remaining over the residual ramus, tear of the retrodiscal tissue or capsule, and joint effusion. The outcome variables were the MRI comparisons of the disc position, healing status of the retrodiscal tissue and capsule, and resolution of joint effusions. RESULTS: Twelve patients, all with ICFs, were included in the present study. Immediately after injury, all 17 fractures (100%) showed anteromedial displacement of both the disc and the fractured condylar fragment, and 10 fractures (58.8%) showed anteromedial displacement of the condylar fragment with the disc remaining over the residual condyle. Also, 11 (64.7%) showed evidence of perforation of the retrodiscal tissue, and 7 (41.2%) showed tears in the capsule. Finally, all 17 (100%) exhibited joint effusions. At 3 months after injury, all 17 fractures (100%) continued to exhibit displacement of both the disc and the condylar segments. Also, 15 fractures (88.2%) showed elongation of the disc and thickening of the retrodiscal tissue, 2 fractures (11.8%) had developed osteoid hyperplasia and meniscal perforation, and 6 fractures (35.3%) showed resolution of previous joint effusions. Finally, 17 fractures (100%) showed reactive bone formation at the condylar head. CONCLUSIONS: ICFs treated with closed reduction consistently result in a specific pattern of temporomandibular joint pathologic features. These pathologic features are characterized by anteromedial displacement of the articular disc, elongation and thickening of the retrodiscal tissue, and reactive bone formation at the condylar head. The presence of a portion of the disc between the residual condyle and the fossa prevented the development of osteoarthritis and ankylosis. Perforation of the bilaminar tissue and contact between the residual condyle and the fossa promoted osteoarthritic changes and ankylosis.

Finite-element analysis of 3 situations of trauma in the human edentulous mandible.

PURPOSE: Maxillofacial trauma resulting from falls in elderly patients is a major social and health care concern. Most of these traumatic events involve mandibular fractures. The aim of this study was to analyze stress distributions from traumatic loads applied on the symphyseal, parasymphyseal, and mandibular body regions in the elderly edentulous mandible using finite-element analysis (FEA). MATERIALS AND METHODS: Computerized tomographic analysis of an edentulous macerated human mandible of a patient approximately 65 years old was performed. The bone structure was converted into a 3-dimensional stereolithographic model, which was used to construct the computer-aided design (CAD) geometry for FEA. The mechanical properties of cortical and cancellous bone were characterized as isotropic and elastic structures, respectively, in the CAD model. The condyles were constrained to prevent free movement in the x-, y-, and z-axes during simulation. This enabled the simulation to include the presence of masticatory muscles during trauma. Three different simulations were performed. Loads of 700 N were applied perpendicular to the surface of the cortical bone in the symphyseal, parasymphyseal, and mandibular body regions. The simulation results were evaluated according to equivalent von Mises stress distributions. RESULTS: Traumatic load at the symphyseal region generated low stress levels in the mental region and high stress levels in the mandibular neck. Traumatic load at the parasymphyseal region concentrated the resulting stress close to the mental foramen. Traumatic load in the mandibular body generated extensive stress in the mandibular body, angle, and ramus. CONCLUSIONS: FEA enabled precise mapping of the stress distribution in a human elderly edentulous mandible (neck and mandibular angle) in response to 3 different traumatic load conditions. This knowledge can help guide emergency responders as they evaluate patients after a traumatic event.

Biomechanical comparison of osteosynthesis with poly-L-lactic acid and titanium screw in intracapsular condylar fracture fixation: An experimental study.

BACKGROUND AND AIMS: The aim of this study was to compare the biomechanical stability of poly-L-lactic acid and titanium screws in the fixation of intracapsular condylar fractures, in 10 polyurethane hemimandibles. MATERIALS AND METHODS: Artificial intracapsular fractures were created with a steel disk and electronic micromotor. The first group was fixed with 15 mm long self-tapping 2.0 mm system titanium screws and the second group was fixed with 15 mm long 2.4 mm bioresorbable screws. Linear loads of 25, 50, 75, 100 N was applied in anteroposterior direction to the hemimandibles and the data were transmitted directly from the load cell to a computer that shows emergent results of material characteristics under same forces as a graphic containing force and displacement. RESULTS: The results show that there were no significant differences between the two methods, with 25 N of loading. (P > 0,05) The difference became significant with a higher value of loading. CONCLUSION: The results suggest that treatment with a single resorbable screw is not functionally stable as a single titanium screw.

Biomechanical evaluation of various rigid internal fixation modalities for condylar-base-associated multiple mandibular fractures: A finite element analysis.

Condylar-base-associated multiple mandibular fractures are more prevalent than single ones. Direct trauma to mandibular symphysis, body or angle are prone to induce indirect condylar fracture. However, little is known about the effects of various rigid internal fixation modalities in condylar base for relevant multiple mandibular fractures, especially when we are confused in the selection of operative approach. Within the finite element analysis, straight-titanium-plate implanting positions in condylar base contained posterolateral zone (I), anterolateral zone (II), and intermediate zone (III). Von Mises stress (SS) in devices and bone and mandibular displacement (DT) were solved, while maximum values (SSmax and DTmax) were documented. For rigid internal fixation in condylar-base-and-symphysis fractures, I + II modality exhibited least SSmax in screws and cortical bone and least DTmax, I + III modality exhibited least SSmax in plates. For rigid internal fixation in condylar-base-and-contralateral-body fractures, I + III modality exhibited least SSmax in screws and cortical bone, I + II modality exhibited least SSmax in plates and least DTmax. For rigid internal fixation in condylar-base-and-contralateral-angle fractures, I + III modality exhibited least DTmax. The findings suggest that either I + II or I + III modality is a valid guaranty for rigid internal fixation of condylar base fractures concomitant with symphysis, contralateral body or angle fractures.

Effect of autologous platelet-rich plasma on bone regeneration in mandibular fractures.

OBJECTIVES: The aim of this study was to assess the effect of autologous platelet-rich plasma (PRP) on bone regeneration in mandibular fractures via a cone beam computed tomography (CBCT). PATIENTS AND METHODS: Twenty-four patients having parasymphyseal fractures participated in this study. They were randomly divided into two equal groups. Group A was treated by two titanium miniplates and screws plus local application of activated PRP along the fracture line, whereas group B was treated by the same bone plates and screws without application of PRP. The patients were recalled at 1 week, 3 and 6 months after surgery for clinical assessment and measuring the bone density via CBCT at a region of interest (ROI) including the fracture line. RESULTS: The mean values of the bone density measurements, in both groups, were higher at 3 and 6 months than 1 week after surgery. At 1 week after surgery, the values were 542 ± 93 HU and 515 ± 81 HU in group A and B, respectively. In group A, the mean value of bone density measurements was 728 ± 58 HU (range 620-796 HU) at 3 months after surgery and it was 1024 ± 188 HU (range 825-1490 HU) 6 months later. While in group B, the mean values of the bone density measurements at the ROI were 600 ± 78 HU (range 520-790 HU) and 756 ± 53 HU (range 710-890 HU) at 3 and 6 months after surgery, respectively. The increase in the bone density measurements at 3 and 6 months after surgery was statistically significant only in group A (P = 0.0002 and P = 0.0001, respectively). CONCLUSIONS: It can be concluded that direct application of the PRP along the fracture lines may enhance the bone regeneration in mandibular fractures.

Effects of internal rigid fixation on mandibular development in growing rabbits with mandibular fractures.

PURPOSE: The aim of this research was to determine whether rigid internal fixation interferes with mandibular growth and development in growing New Zealand white rabbits with induced mandibular fractures. MATERIALS AND METHODS: Ten 3-month-old New Zealand white rabbits were included in the study. Surgical fractures were performed in the right mandibular bodies of the 10 rabbits. These fractures were reduced with internal rigid fixation by use of a 1.0-mm titanium system, taking the contralateral left mandibular bodies as the control group. We obtained radiographs preoperatively and at 1, 2, and 3 months postoperatively. Predetermined cephalometric points were used to measure and compare jaw growth. The protocol was approved by the Bioethics Committee of Universidad El Bosque, Bogotá, Colombia. RESULTS: There were no statistically significant differences between the experimental and control groups (P = .95). Mandibular growth in the studied rabbits was not affected by the use of internal rigid fixation. CONCLUSIONS: The use of internal rigid fixation for the treatment of induced mandibular fractures in growing rabbits did not alter the normal process of growth and development. The findings of this study should lead to investigations using larger samples and to long-term prospective follow-up studies of children who have undergone open reduction and internal rigid fixation.

Does traumatic brain injury result in accelerated mandibular fracture healing?

PURPOSE: To investigate the occurrence of accelerated bone healing evidenced by early callus formation in patients with mandibular fractures and traumatic brain injury (TBI). MATERIALS AND METHODS: A retrospective cohort study was performed in patients who presented for mandibular fracture evaluation and management over a 6-year period. Subjects eligible for the study included those who underwent a computed tomographic examination of the mandible more than 2 weeks after the injury and had not undergone surgery with rigid internal fixation. TBI was used as the predictor variable. Time to callus formation as detected on computed tomographic scans was recorded as the primary outcome variable. Other variables considered included age, gender, coma duration, and fracture distribution. Appropriate statistical analyses were performed to determine the influencing factors. RESULTS: Forty-five patients with mandibular fractures (24 with severe TBI and 21 without TBI) were retrospectively analyzed. Twelve patients with TBI and 6 without TBI exhibited a visible callus on their computed tomographic scans. Statistical analysis showed no significant differences in age, gender, examination time, and fracture distribution between the groups. Cox proportional hazards regression analysis indicated a positive correlation of time to callus formation with TBI and coma duration but not with age, gender, and fracture distribution. CONCLUSIONS: These findings suggest that patients with severe TBI and mandibular fractures exhibit increased fracture healing as evidenced by early callus formation. A more exhaustive study is required to advance the understanding of this phenomenon and provide additional clinical significance.

Mandibular condylar growth in growing rats after experimentally displaced condylar fracture with associated attachment damage and disc displacement: an observation by polychrome sequential labeling.

PURPOSE: The purpose of this study was to evaluate mandibular condylar growth in growing rats after experimentally displaced condylar fracture with associated attachment damage and disc displacement by means of polychrome sequential labeling. MATERIALS AND METHODS: We randomized 30 growing male Wistar rats into 3 equal groups: rats with experimentally displaced condylar fractures with associated attachment damage and disc displacement (experimental group); rats with experimentally displaced condylar fractures without associated attachment damage and disc displacement (control group); and rats that received no operative intervention (negative control group). Polychrome sequential labeling was used to establish chronologically oriented condylar growth characteristics in these rats. Three months after the operation, the specimens were obtained, fixed, dehydrated, and embedded in acrylic resin for fluorescence microscopy observation. In addition, the lateral-medial diameter (in millimeters) and mineral apposition rate (in micrometers per day) of condyles were measured and analyzed across the 3 groups. RESULTS: The results showed condylar growth disturbance in the experimental group rats, presenting with no obvious and regular bone growth lines in the anamorphic condyle. However, in the control group and negative control group rats, the condylar growth was normal. Regarding the lateral-medial diameter and mineral apposition rate, there was a significant difference between the experimental group and control group, as well as between the experimental group and negative control group; however, there was no significant difference between the control group and negative control group. CONCLUSIONS: The occurrence of associated attachment damage and disc displacement in condylar fractures should be considered an important factor influencing the condylar growth after fracture.

Electromyographic study in patients with surgically treated facial fractures.

This study, using surface electromyography, analyzed the activity of the masseter muscles of 30 patients with facial bone fractures that were surgically treated. Evaluations were made before surgery and in the 7th, 30th, and 60th days after surgery. The value of each measure and the average of 3 maximum voluntary isometric contractions lasting 5 seconds each were registered, and statistical analyses were performed. Patients had a mean age of 31 years and an average of 1.33 fractures. They were grouped according to the type of fracture as follows: mandibular (50%), zygomatic complex (33%), maxilla (10%), and associated fractures (6.7%). There was a lower masseter activity in the preoperative period, when compared with normal values in all groups of fractures. There was a sharp drop in the masseter activity in the postoperative period of 7 days, and all groups showed recovery of activity in 60 days but still below the normal value referenced in the literature. The mean values of the masseter activity, in descending order, were from the zygomatic complex, mandibular, maxillary, and associated fractures. The unilateral mandibular fractures showed higher values than the bilateral fractures in most of the evaluations. There was a highly significant difference in the comparison of the evolution of the masseter activity on both sides, for mandibular and zygomatic complex fractures, and the pairwise comparison showed significant difference between most groups. It was concluded that facial fractures and surgical procedures had negative effects in the muscle activity as observed using electromyography.

Intra-articular fracture of the mandibular condyle: a case report.

The authors describe a case of intra-articular fracture of the left mandibular condyle, successfully treated by the pumping technique in the upper and lower joint cavities, and show arthroscopic findings in these cavities. The patient was a 15-year-old boy whose maximum mouth opening was 30 mm. Computed tomography revealed a left intra-articular sagittal fracture of the condylar head. Aspiration of the hematoma in the upper and lower joint spaces was performed with ten pumping actions. In the upper and lower joint spaces, arthroscopic examination revealed the disappearance of the hematoma. The patient continued opening, protrusive, and lateral excursive exercises. One month after the surgery, the maximal interincisal distance was improved to 45 mm with straight opening. In the case presented, mouth-opening exercises, along with the pumping technique for treatment of an intraarticular fracture of the mandibular condyle, allowed satisfactory and stable results in the improvement of limited mouth movement.