Mandibular Titanium Miniplates Change the Biomechanical Behaviour of the Mandible in the Case of Facial Trauma: A Three-Dimensional Finite Element Analysis.

Our study aimed to compare the biomechanical behaviour of mandibles with or without titanium miniplates when subjected to an impact after bone healing using a finite element model (FEM) of the human mandible. We simulated mandibular trauma on an FEM of a human mandible carrying or not two parasymphyseal miniplates and applying a concentrated force of 2000 N to four different areas, including the insertion area, the area straddling the edge of the miniplates and the adjacent bone, at a distance from the miniplates on the symphysis, and on the basilar border of the mandible below the miniplates. Then, we compared the Von Mises stress distributions between the two models. In the case of an impact on the miniplates, the maximum Von Mises stress occurred in two specific areas, on the cortical bone at the posterior border of the two miniplates at a distance from the impact, while in the model without miniplates, the Von Mises stresses were homogenously distributed in the impact area. The presence of titanium miniplates in the case of trauma affects the biomechanical behaviour of the mandible and could cause more complex fractures. We recommend informing patients of this potential risk.

Effect of bone density on the survival of 407 sandblasted and acid-etched dental implants: A retrospective multicenter study.

Background: This study evaluated the success and survival rate of sandblasted and acid-etched dental implants according to the patient's bone quality. Methods: A multicenter retrospective study was conducted in five clinical centers between 2016 and March 2019. A total of 407 implants (KONTACTTM S, Biotech Dental, France) placed in 229 patients (61.5±12.9 years old) were included. Bone quality, classified as types D1 to D4 (Misch classification), maximal insertion torque, and bone loss were measured. The implant survival rate was evaluated after one year for the overall cohort and for each bone quality. The overall survival rate after four years was also estimated with a Kaplan-Meier analysis. Results: After one year (12.8±9.6 months), eight implants were lost out of 407, representing an overall survival rate of 98%. It ranged from 100% for D1 to 89.7% for D4 (n=39), with significantly higher survival rates for D2 (n=93) and D3 (n=165) (98.9% and 98.2%, respectively) compared to D4. According to the Kaplan-Meier analysis, an overall survival rate of 96.5% was estimated after four years. An average maximal insertion torque of 45±12.6 N.cm and bone loss of 0.2±1.2 mm were measured. Conclusion: The high overall survival rate (98%), the average maximal insertion torque (45 N.cm), and the low marginal bone loss indicated good clinical results with acid-etched implants. Despite the relatively high survival rate for each bone quality, the significantly lower results in the D4 group highlight the expected benefits of bone quality-based implants and surgical protocols.

Effect of LED photobiomodulation on dental implant osseointegration: An in vivo study.

Background: Photobiomodulation (PBM) may be prescribed after dental surgery to accelerate tissue healing and improve implant stability. The objective of this study is to evaluate the efficiency of LED-PBM on the dental implant osseointegration. Methods: A total of 48 implants (KontactTM) were inserted in 8 Yucatan minipigs (6 implants per minipig) divided into 2 groups (test and control). The test group received LED-PBM with a total energy of 124.2 J/cm2 delivered over 4 sessions (at day0, day+8, day+15 and day+28) lasting 12 minutes each. At day+28, all animals were sacrificed, and their mandibles removed to perform histologic and histomorphometric analysis. Implant osseointegration was evaluated using the computation of bone/implant contact (BIC) index and bone surface/total surface (BS/ TS) ratio. The groups were compared using Student's unpaired t test. Results: BIC index and BS/TS ratio were significantly higher within the test group as compared to the control group (P<0.01). Histologic observations on bone tissues demonstrated that LED-PBM may improve and accelerate dental implant osseointegration: 25% of dental implants analyzed within the test group were completely osseointegrated, versus 12.5% within the control group. Conclusion: This experimental study indicates that LED-PBM contributes to enhancing implant treatment outcomes.

Experimental analysis and numerical fatigue life prediction of 3D-Printed osteosynthesis plates.

The trend towards patient-specific medical orthopedic prostheses has led to an increased use of 3D-printed surgical implants made of Ti6Al4V. However, uncertainties arise due to varying printing parameters, particularly with regards to the fatigue limit. This necessitates time-consuming and costly experimental validation before they can be safely used on patients. To address this issue, this study aimed to employ a stress-life fatigue analysis approach coupled with a finite element (FE) simulation to estimate numerically the fatigue limit and location of failure for 3D-printed surgical osteosynthesis plates and to validate the results experimentally. However, predicting the fatigue life of 3D components is not a new concept and has previously been implemented in the medical device field, though without experimental validation. Then, an experimental fatigue test was conducted using a proposed modification to the staircase method introduced in ISO 12107. Additionally, a FE model was developed to estimate the stress cycles on the plate. The stress versus number of cycles to failure curve (S-N) obtained from the minimum mechanical properties of 3D-printed Ti6AI4V alloy according to ASTM F3001-14 to predict the fatigue limit. The comparison between experimental results and fatigue numerical predictions showed very good agreement. It was found that a linear elastic FE model was sufficient to estimate the fatigue limit, while an elastic-plastic model led to an accurate prediction throughout the implant's cyclic life. The proposed method has great potential for enhancing patient-specific implant designs without the need for time-consuming and costly experimental regulatory testing.

Surgical techniques used in chin feminization: Literature review and knowledge update.

Genioplasty is commonly performed as part of facial feminization surgery. Commonly addressed areas in facial feminization surgery include the chin. According to some authors, 100% of patients request genioplasty surgery in order to feminize their faces. Specific genioplasty techniques (involving generally reduction surgery) applied to transgender patients have been rarely described in the literature. Objective: We aimed to carry out a review of the literature to update the current knowledge on this subject while achieving a comprehensive synthesis of the available surgical techniques for reduction genioplasty in trans Male to Female patients. Conclusion: Reduction genioplasty is frequently performed in facial feminization surgery. Multiple surgical techniques for chin feminization have been described in the existing literature. Reduction genioplasty requires combined work in the sagittal and transverse planes so as to obtain a harmonious result. However, no comparative study on the different surgical techniques has as yet been conducted. Patient satisfaction or surgical complications (which tend to be rare) cannot be related to any specific surgical technique.

Do mandibular titanium miniplates affect the biomechanical behaviour of the mandible? A preliminary experimental study.

INTRODUCTION: Whether to conserve or remove titanium miniplates after rigid internal fixation of mandibular fractures still remains controversial. Miniplates could affect the biomechanical behaviour of the mandible in case of trauma, and therefore cause more complex fractures. MATERIALS AND METHODS: An experimental study, consisting in simulating a mandibular trauma, was designed in order to compare the fractures caused by an impact on the mandible in the presence or absence of an internal fixation. We simulated an impact on the right parasymphysis region in 10 post-mortem human subjects, according to the Charpy impact test method at an impact speed of 7.4 m/s, using a 5 kg test impactor. RESULTS: In the control group, the fracture lines were vertical and straight, without comminution. In the miniplate group, the fractures occurred close to the miniplates (4 cases) and under the miniplates (one case). The fracture lines were more complex, even comminuted in 2 cases. Thus, miniplates impacted the biomechanical behavior of the mandible, resulting in more complex fractures. CONCLUSION: Our experimental study highlighted the impact of the presence of miniplates on the mandible in case of trauma, and the risk of causing more complex fractures. We therefore recommend further investigations to determine if titanium miniplates should be systematically removed after bone healing, in patients with a higher risk of trauma in relation with previous assault injuries, alcohol or substance abuse, the practice of fighting or contact sport/activities, and soldiers.

Is minor surgery safe during the COVID-19 pandemic? A multi-disciplinary study.

BACKGROUND: To assess the risk of postoperative SARS-CoV-2 infection during the COVID-19 pandemic. METHODS: The CONCEPTION study was a cohort, multidisciplinary study conducted at Conception University Hospital, in France, from March 17th to May 11th, 2020. Our study included all adult patients who underwent minor surgery in one of the seven surgical departments of our hospital: urology, digestive, plastic, gynecological, otolaryngology, gynecology or maxillofacial surgery. Preoperative self-isolation, clinical assessment using a standardized questionnaire, physical examination, nasopharyngeal RT-PCR and chest CT scan performed the day before surgery were part of our active prevention strategy. The main outcome was the occurrence of a SARS-CoV-2 infection within 21 days following surgery. The COVID-19 status of patients after discharge was updated during the postoperative consultation and to ensure the accuracy of data, all patients were contacted again by telephone. RESULTS: A total of 551 patients from six different specialized surgical Departments in our tertiary care center were enrolled in our study. More than 99% (546/551) of included patients underwent a complete preoperative Covid-19 screening including RT-PCR testing and chest CT scan upon admission to the Hospital. All RT-PCR tests were negative and in 12 cases (2.2%), preoperative chest CT scans detected pulmonary lesions consistent with the diagnosis criteria for COVID-19. No scheduled surgery was postponed. One patient (0.2%) developed a SARS-CoV-2 infection 20 days after a renal transplantation. No readmission or COVID-19 -related death within 30 days from surgery was recorded. CONCLUSIONS: Minor surgery remained safe in the COVID-19 Era, as long as all appropriate protective measures were implemented. These data could be useful to public Health Authorities in order to improve surgical patient flow during a pandemic.

Do mandibular miniplates increase the risk of complex fracture in facial trauma recurrence? Case series.

Whether to conserve or remove miniplates, widely used in oral and maxillofacial surgery, has not been agreed on in the literature. Complications such as pain, infection, and screw exposure or loosening have already been largely described. We present the consequences of a trauma recurrence on a mandible with miniplates. The data of 13 patients who had a mandibular fracture previously surgically treated with miniplates (ten mandibular fractures and three mandibular osteotomies) were analysed. All the patients were male; the average age was 32 years (range, 20-64 years). The mechanism of the second trauma was assault in most of the cases. The average time between the first osteosynthesis and the new fracture was 35 months (range, 6-128 months). The fractures occurred at a distance from the miniplates in all the cases except two. No plate fracture was reported. We hypothesised that miniplates reinforced the underlying bone, protecting it from fractures, and transmitted the forces to areas anterior or posterior to the miniplates or to the condyle. Thus, the risk of mandible trauma recurrence should be taken into account in the indication of plate removal, and the biomechanical consequences of the conservation of the miniplates should be studied.

Salivary Gland Lithiasis Recurrence After Minimally-Invasive Surgery: Incidence, Risk Factors and Prevention.

OBJECTIVE: The aim of this study was to evaluate the recurrence rate of lithiasis following minimally invasive surgery to identify risk factors and mechanisms for recurrence of salivary gland lithiasis. STUDY DESIGN: Retrospective case series. METHODS: A retrospective study was conducted including all patients treated for salivary gland lithiasis by minimally invasive surgery, such as sialendoscopy, intracorporeal lithotripsy, extracorporeal lithotripsy, transoral approach, and combined approach in our Department. We analyzed the recurrence rate of salivary lithiasis, their topography and timeline. RESULT: Three hundred four patients were included in this study, the mean age was 49 years (range 12-90 years), and the mean duration of follow-up was 19.8 months (range 0-66 months). Fifteen patients (5%) presented secondary lithiasis. In all but one case, recurrences involved the same gland as primary lithiasis, and most frequently the submandibular gland. Recurrences occurred from 3 to 46 months postoperatively. Fourteen patients, who presented recurrence, had been initially treated by transoral approach. Recurrent lithiasis were treated by transoral approach or submandibulectomy. CONCLUSION: Salivary gland lithiasis recurrence was rare after minimally invasive salivary gland surgery. This study reinforced the concept that salivary gland lithiasis should be considered as a duct pathology. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:794-799, 2021.

The association of Le Fort midfacial fractures with frontobasal injuries: a 17-year review of 125 cases, reflections on biomechanics, classifications and treatment.

The frequency of midface and frontobasal fractures has increased over the past 40 years despite the improvement and stringent regulation implemented on modern safety equipment (belts, helmets…). This observation might be correlated with the progress of radiodiagnosis tools. Literature was reviewed according to Prisma guidelines. We searched for reviewed articles, published between January 2000 and December 2017, through Medline (Pubmed) online databases and ScienceDirect, using the following MeSH Keywords: "Le Fort classification", "Le Fort fracture", "Frontobasal fracture", "skull base fracture", "Midface Fractures". Among 652 patients with frontobasal fractures, 125 (19.1%) were associated with a Le Fort fracture. 59 (9%) were associated with Le Fort III fracture, 51 (7.8%) with Le Fort II fracture and 15 (2.3%) with Le Fort I fracture. When frontobasal fractures were associated with midfacial fractures, we found 18 cerebrospinal fluid leaks (11.8 %) and 19 cases of meningitis (12.5 %). When only the frontobasal area was involved, there were 6 cerebrospinal fluid leaks (4.3 %) and 6 meningitis (4.3 %). Our results highlight a regular association between Le Fort fractures and frontobasal fractures for stages II and stage III of Le Fort fractures and also found a higher rate of neuro-septic complication. Further research shall investigate treatment and monitoring recommendations fitting modern epidemiology of craniofacial traumatology.

Salivary side effects after radioiodine treatment for differentiated papillary thyroid carcinoma: Long-term study.

BACKGROUND: Although many studies focus on short-term side effects of radioiodine therapy, almost none studied long-term side effects. We assessed radioiodine long-term salivary side effects after radioiodine treatment for differentiated papillary thyroid carcinoma and compared it to short-term morbidity within the same population. METHODS: A standardized self-administrated questionnaire was submitted in 2019 by patients treated with radioiodine between January 2011 and December 2012. These patients had already answered the same questionnaire 6 years before. RESULTS: Our study showed a significant reduction for salivary side effects: discomfort in submandibular or parotid area, swelling, pain, a bad or salty taste in the mouth, allowing to get back to a "normal" diet. CONCLUSIONS: Our study suggests that a significant rate of patients will recover from I131 therapy salivary side effects. As almost 30% of these remissions happened during our late stage follow-up, we highlight the necessity of a long-term follow-up in these patients.

Standard and Customized Alloplastic Facial Implants Refining Orthognathic Surgery: Outcome Evaluation.

PURPOSE: Conventional orthognathic osteotomies provide appropriate functional outcomes but might be unable to correct midface deficiency, achieve a satisfactory outcome in asymmetrical cases, or allow sufficient chin advancement. We evaluated the outcome of both standard and customized facial high-density porous polyethylene implants used to refine the cosmetic outcome of orthognathic surgery. PATIENTS AND METHODS: We implemented a retrospective study. The sample was composed of all patients who underwent facial alloplastic augmentation between June 2011 and October 2018 in our department. The complication rate was recorded after a mean follow-up period of 41 months postoperatively, and patient satisfaction was assessed through a qualitative evaluation based on an 11-item questionnaire. RESULTS: The sample was composed of 24 implants placed in 14 patients: 13 mandibular angle implants, among which 4 were customized; 8 malar implants; and 3 chin implants. No physical complications such as hematoma, infection, migration, or hypoesthesia were observed. Two implants had to be removed because of early unsatisfactory esthetic outcomes. Of 14 patients, 11 answered our questionnaire. Eighty-two percent strongly agreed that the overall outcome was satisfactory. CONCLUSIONS: The results of this study confirm the low physical complication rate described in the literature, and the esthetic complication rate remains lower than the rates observed in previous reports. A high satisfaction rate was found among patients. The lowest mean satisfaction score was noted for appropriate implant symmetry (3.5), whereas the highest mean satisfaction score (3.8) was achieved when using customized implants. If standard high-density porous polyethylene implants appear to be relevant adjuncts to orthognathic surgery, customized implants seem to achieve higher satisfaction, although their prohibitive cost should be considered.

Sialendoscopy-Assisted Duct Transposition in Ectopic Accessory Parotid Gland: Case Report and Surgical Management.

An ectopic accessory parotid gland with a congenital cheek fistula is a rare congenital condition that belongs to the oculoauriculovertebral spectrum. The clinical symptom is generally a cheek fistula. Surgical treatment can include either the removal of the ectopic gland or a duct transposition. We describe a sialendoscopy-assisted duct transposition and its associated surgical management. Sialendoscopy helped identify the fistula tract through the mucosa. Sialendoscopy-assisted duct transposition in treating an ectopic accessory parotid gland proved to be a safe and minimally invasive procedure. The required incisions were small, which makes this type of surgery more straightforward and more precise.

Could mastication modify the shape of the orbit? A scannographic study in humans.

PURPOSE: Since prehistory, changes of the facial skeleton have been related to the modification of diet. More recent studies have shown changes in the morphology of the mandible and maxilla due to variations of strain during mastication. The temporal muscle (TM) is a strong masticatory muscle, with its insertions extending through the temporal fossa. Our objective is to observe the relations between the TM and the lateral orbital wall (LOW) which could indicate an influence of mastication on the shape of the LOW. METHODS: We conducted a retrospective study using 100 CT scans. The length of the lateral orbital wall (LLOW), the angle between LOW and the medial orbital wall (MOW), the cross-sectional areas of LOW and of the TMs were measured on both sides of each CT scan. The correlation between TMs and other three parameters was studied by Pearson correlations. RESULTS: A correlation was found between TMs and LOWs, a lower with LLOW, and a very weak and negative correlation between LOW/MOW angle. CONCLUSIONS: Anatomical knowledge about TM and investigation of masticatory strains lead us to think that mastication have minimal effect on the morphology of the LOW, only on the frontal process of zygomatic. This may explain, in part, why the LOW is the strongest wall of the orbit.

Bioactive glass 45S5 ceramic for alveolar cleft reconstruction, about 58 cases.

BACKGROUND: Secondary alveolar bone grafting in patients with clefts lip and palate is usually performed with iliac crest bone harvesting, however using bone substitute allow to avoid harvesting morbidity. The purpose of our study was to assess if the use of a bioactive glass ceramic is an acceptable alternative to iliac crest bone harvesting in alveolar clefts treatment. METHODS: A prospective study including all patients who have benefited of alveolar grafting by GlassBONE™ (Noraker, France), a synthetic resorbable bioactive glass 45S5 ceramic was conducted. The patients underwent clinical assessments and imaging check-up by dental panoramic radiography and CBCT. RESULTS: Fifty-eight graftings were performed. The mean age at the time of the graft was 7.6 years. Hospitalization, social eviction and antalgic consumption were reduced. Bone continuity was achieved in 63.8% of the cases. Bilateral cleft and dental agenesia increased grafting failure. In the subgroup of 25 patients with isolated unilateral cleft without dental agenesis, 80% had bone continuity at one year. We noted 10.3% of alveolar fistula recurrence. CONCLUSION: The use of GlassBONE™ in alveolar grafts simplifies the surgery procedure and the postoperative management, and ensures satisfactory mucosal healing, tooth eruption and bone continuity in two thirds of the followed grafts.

Is Preoperative Maintenance of the Curve of Spee Associated With an Increase of Facial Height in Class II Short Face Orthognathic Patients? A Never Answered Dogmatic Question.

PURPOSE: To determine the association of maintaining the curve of Spee (COS) before surgery with post-treatment facial height in patients with Class II short face syndrome undergoing combined orthodontic and orthognathic treatment. MATERIALS AND METHODS: In this retrospective cohort study, the clinical and radiologic data of all patients with Class II short face syndrome who underwent combined orthodontic and orthognathic treatment were reviewed. The primary outcome variables were 1) preoperative COS and 2) post-treatment facial height. Depth of the COS and skeletal and soft tissue relations were measured on digital lateral cephalometric radiographs. Descriptive and bivariate statistics were performed. RESULTS: The sample was composed of 20 patients. Statistical analysis showed a significant increase of soft tissue facial height after treatment (P < .02). Preoperative depth of the COS was significantly associated with changes in sagittal skeletal relations (angle formed by the sella, nasion, and B point [SNB], correlation [cor] = -0.54, P < .02; angle formed by the A point, nasion, and B point [ANB], cor = 0.43, P < .06). These changes and changes in overjet were associated with the post-treatment increase of lower facial height (SNB, cor = 0.70, P < .001; ANB, cor = -0.69, P < .001; overjet, cor = -0.55, P < .049). The ratios of upper to lower soft tissue facial height and upper to lower lip height were improved to near normal values (1.0 and 0.5, respectively) for most patients. CONCLUSION: In patients with Class II short face orthognathism, the present study found that maintaining the COS before surgery was associated with 1) an increase of soft tissue facial height and 2) an improvement of the ratio of upper to lower facial height and the ratio of upper to lower lip height to near normal values. Moreover, the depth of the COS was correlated with the post-treatment increase of facial height through changes in skeletal relations and was related to the degree of severity of the mandibular deficiency.

Orbital Reconstruction by Patient-Specific Implant Printed in Porous Titanium: A Retrospective Case Series of 12 Patients.

PURPOSE: The purpose of this study was to evaluate the orbital patient-specific implant (PSI) directly printed in porous titanium for the reconstruction of complex orbital bone defects in a series of 12 patients. PATIENTS AND METHODS: The authors designed and implemented a case series. The sample consisted of patients with unilateral complex orbital bone loss. All patients received a porous titanium PSI designed from the healthy contralateral side (mirroring). The criteria analyzed were the functional results: correction of enophthalmos, correction of ocular motility, operative time, complications, and operative revisions. The study was performed from 2015 through 2017. RESULTS: The sample was composed of 12 patients (mean age, 47 yr; age range, 13 to 70 yr). Patients were followed for a mean of 36 weeks postoperatively (range, 4 to 100 weeks). Twelve of the 12 patients presented preoperative enophthalmia, and 8 of the 12 patients presented preoperative diplopia. The mean operating time was 71 minutes (range, 60 to 200 minutes). For 8 patients, the follow-up was simple. In contrast, 2 patients required surgical revision with repositioning of the implant because of intraoperative implant malpositioning with esthetic or functional disturbance and malpositioning was confirmed on the postoperative computed tomogram, 1 patient required explantation of his implant 7 months after the surgery because of spheno-orbital meningioma recurrence (the implant was well positioned), and 1 patient operated on by a subciliary approach presented a postoperative ectropion. In this series of porous titanium orbital PSIs without positioning guides, 17% had malpositioning (2 patients who required a new intervention for repositioning). CONCLUSION: The results of this study suggest that porous titanium PSI could be a surgical option for patients with complex orbital bone defects. In this series 17% of the sample needed a second operation. There are several ways to improve these results, such as intraoperative navigation or integrated positioning guides.