Which experimental models and explorations to use in regenerative endodontics? A comprehensive review on standard practices.

Since the discovery of dental pulp stem cells, a lot of teams have expressed an interest in dental pulp regeneration. Many approaches, experimental models and biological explorations have been developed, each including the use of stem cells and scaffolds with the final goal being clinical application in humans. In this review, the authors' objective was to compare the experimental models and strategies used for the development of biomaterials for tissue engineering of dental pulp with stem cells. Electronic queries were conducted on PubMed using the following terms: pulp regeneration, scaffold, stem cells, tissue engineering and biomaterial. The extracted data included the following information: the strategy envisaged, the type of stem cells, the experimental models, the exploration or analysis methods, the cytotoxicity or viability or proliferation cellular tests, the tests of scaffold antibacterial properties and take into account the vascularization of the regenerated dental pulp. From the 71 selected articles, 59% focused on the "cell-transplantation" strategy, 82% used in vitro experimentation, 58% in vivo animal models and only one described an in vivo in situ human clinical study. 87% used dental pulp stem cells. A majority of the studies reported histology (75%) and immunohistochemistry explorations (66%). 73% mentioned the use of cytotoxicity, proliferation or viability tests. 48% took vascularization into account but only 6% studied the antibacterial properties of the scaffolds. This article gives an overview of the methods used to regenerate dental pulp from stem cells and should help researchers create the best development strategies for research in this field.

Odontoblastic differentiation of dental pulp stem cells from healthy and carious teeth on an original PCL-based 3D scaffold.

AIMS: To isolate and characterize dental pulp stem cells (DPSCs) obtained from carious and healthy mature teeth extracted when conservative treatment was not possible or for orthodontic reasons; to evaluate the ability of DPSCs to colonize, proliferate and differentiate into functional odontoblast-like cells when cultured onto a polycaprolactone cone made by jet-spraying and prototyped into a design similar to a gutta-percha cone. METHODOLOGY: DPSCs were obtained from nine carious and 12 healthy mature teeth. Then cells were characterized by flow cytometry and submitted to multidifferentiation to confirm their multipotency. These DPSCs were then cultured on a polycaprolactone cone in an odontoblastic differentiation medium. Cell proliferation, colonization of the biomaterial and functional differentiation of cells were histologically assessed. For the characterization, a t-Student test was used to compare the two groups. RESULTS: In all cell cultures, characterization highlighted a mesenchymal stem cell phenotype (CD105+, CD90+, CD73+, CD11b-, CD34-, CD45-, HLA-DR-). No significant differences were found between cultures obtained from carious and healthy mature teeth. DPSCs from both origins were able to differentiate into osteocytes, adipocytes and chondrocytes. Cell colonization was observed both on the surface and in the thickness of polycaprolactone cones as well as a mineralized pericellular matrix deposit composed of type I collagen, alkaline phosphatase, osteocalcin and dentin sialophosphoprotein. CONCLUSIONS: DPSCs were isolated from both carious and healthy mature teeth. They were able to colonize and proliferate within a polycaprolactone cone and could be differentiated into functional odontoblast-like cells.

[Type 2 dens fracture in the elderly and therapy-linked mortality : Conservative or operative treatment]. / Typ-II-Densfrakturen des alten Menschen und therapiebedingte Mortalität : Konservative oder operative Behandlung.

BACKGROUND: Type II fractures of the odontoid process of the axis are the most common injury of the cervical spine in elderly patients. Only little evidence exists on whether elderly patients should be treated conservatively or surgically. MATERIAL AND METHODS: The mortality and survival probability of 51 patients were determined in a retrospective study. The range of motion, pain and the neck disability index were clinically investigated. RESULTS: Of the 51 patients 37 were treated surgically and 14 conservatively. The conservatively treated group showed a higher mortality (64 % vs. 32 %). Kaplan-Meier analysis revealed a median survival of the conservatively treated group of 29 months, whereby during the first 3 months of treatment this group showed a higher survival probability and afterwards the surgically treated group showed a higher survival probability. The clinical examination of 20 patients revealed limited range of motion of the cervical spine. Additionally, moderate levels of pain and complaints were recorded using the neck disability index. CONCLUSION: Fractures of the odontoid process pose a far-reaching danger for elderly patients. A balanced assessment of the general condition should be carried out at the beginning of treatment of these patients. In the early phase following trauma no differences were found with respect to survival rates but for long-term survival the operatively treated group showed advantages; however, these advantages cannot be causally attributed to the choice of therapy.

Surgery for inflammatory tumor of the lung caused by pulmonary actinomycosis.

BACKGROUND: Actinomycosis is an uncommon chronic suppurative bacterial infection caused by anaerobic bacteria. Pulmonary actinomycosis is even more infrequent and generally simulates a wide variety of pulmonary disorders including tuberculosis and lung cancer. Therefore delayed diagnosis and misdiagnosis is common. Here, actinomycosis was initially confused with pulmonary carcinoma. METHODS: We report on three cases of inflammatory tumors caused by pulmonary actinomycosis. All three patients were male and had a history of alcoholism and poor oral hygiene associated with dental disease. Clinical symptoms were nonspecific and radiographic imaging showed tumor-like mass lesions not distinguishable from neoplasms. Preoperative bronchoscopy, sputum culture, laboratory tests and bronchoalveolar lavage neither confirmed an infectious disease nor ruled out lung cancer. Hence all patients underwent thoracotomy for both diagnosis and definitive treatment. Intraoperatively we encountered a necrotizing infection forming cavitary as well as tumorous lesions and a lobectomy was performed due to destroyed lung tissue. In one case the tumorous lesion involved the chest wall so that partial resection of the 3rd rib with the adjacent soft tissue was mandatory. RESULTS: Histological examination of the pulmonary specimen established the diagnosis of pulmonary actinomycosis. All patients recovered well and received antibiotic therapy with oral penicillin. CONCLUSIONS: The diagnosis of pulmonary actinomycosis remains challenging. In cases of an inflammatory tumor imitating lung cancer, surgical resection is mandatory, both to confirm the diagnosis and for the definitive treatment in cases with irreversible parenchymal destruction. Here, surgery in combination with medical treatment offered reliably excellent results.

[Membranes in pre-implantation surgery]. / Les membranes en chirurgie pré-implantaire.

The use of membranes in pre-implantation surgery is part of the guided bone regeneration (GBR) concept, one of the usual bone augmentation techniques. Membranes for GBR procedures have two main uses: a mechanical function to maintain bone regeneration space and a physical function as cellular barrier. The goal is to promote colonization of the regeneration space located under the membrane, by osteogenic cells from the residual bone walls. GBR was the subject of numerous publications and protocols since its first use in the 1980s. These protocols are mainly supported by team experience and the level of evidence is poor. Few indications are truly validated. The goal of our study was to review the recent literature on membrane use for pre-implantations surgery, and, in the absence of any consensus, to provide some arguments for their rational use.

An epidemiologic retrospective study of maxillofacial traumatology in the elderly.

INTRODUCTION: The elderly population, which is more active than before, is increasingly suffering from trauma (loss of reflexes and systemic pathologic conditions). Surgical management may be more controversial due to the potential consequences of general anesthesia and the sometimes negligible consequences of functional management. The main objective of this study was to analyze the causes and location of facial fractures in subjects older than 65 years. The secondary objective was to evaluate the management of these fractures (surgical or functional) according to comorbidities. MATERIAL & METHODS: In this retrospective study (over a five-year period), we analyzed the causes and management of facial fractures in patients aged over 65 years, and the medical history of each patient was investigated. RESULTS: One hundred and nineteen patients with 198 facial fractures were included. The main cause of fractures was a fall (50%). The zygomatic region (39.9%) and mandible (27.8%) were the sites of the most frequent fractures. Comorbidities were found in 84.9% of patients, the majority of which were cardiovascular diseases (82.3%). 75.8% of fractures were treated surgically and 4.8% of patients had complications. DISCUSSION: This work is a help to understanding the causes and consequences of facial trauma in the elderly population. The management of these facial fractures requires a multidisciplinary assessment, taking into account the patient's medical history and evaluating the risks and benefits of a surgical procedure with general anesthesia.

Significant decrease of facial cellulitis admissions during COVID-19 lockdown in France: A multicentric comparative study.

During the 2020 coronavirus pandemic, a lockdown was imposed in France during the first wave. An apparent decrease in incidence of cellulitis of odontogenic origin was noticed then. This study aimed to compare the incidence of cellulitis during this extraordinary period with the same period in 2018 and 2019, based on retrospective multicentric data. All maxillofacial surgery departments in French public hospitals were contacted. Responders were asked to include all patients admitted for the surgical drainage of a head and neck abscess of odontogenic origin during the first 2020 lockdown period, and in a similar time frame in 2018 and 2019 (control group), based on screening the French diagnostic and therapeutic classification of medical acts. We report a 44% significant nationwide decrease in the incidence of admissions for cellulitis. There were 187 patients in 2020 for 334 and 333 patients in 2018/2019 respectively. The reasons to explain this finding are hypothetical (organizational reasons leading to earlier management, patients' fear to seek for medical management, usual excess in surgical indications or concomitant decrease of non-steroidal anti-inflammatory drugs delivery). Whatever the explanation, it would be of great interest to find it out in order to improve the prevention of cellulitis.

[Hyalinizing clear cell carcinoma of the maxilla]. / Carcinome hyalinisant à cellules claires du maxillaire.

INTRODUCTION: Hyalinizing clear cell carcinoma (HCCC) of minor salivary glands (MSG) is a rare low-grade malignant neoplasm accounting for less than 1% of all salivary gland tumors. It usually affects the palate and the base of the tongue, and more rarely the parotid gland. We report a very rare maxillary localization. CASE REPORT: A 48-year-old male patient, without prior medical history, was referred to us for a painless gingival lesion of the right maxilla, extending from tooth 14 to 17, having appeared a few months before. The clinical examination was otherwise normal. Biopsy proved the diagnosis of HCCC. The CT scan revealed extension in maxillary sinus with bone osteolysis, and suspicion of cervical lymph nodes metastasis. The treatment was subtotal maxillectomy, cervical lymph node dissection, and postoperative radiotherapy because of incomplete bony resection. DISCUSSION: HCCC localization in the maxilla is extremely rare. This tumor may recur. The risk of metastasis is low; it concerns mainly lymph nodes. There is no treatment protocol consensus because the tumor is rare. Nevertheless, a wide local excision, with or without postoperative radiotherapy, seems to be the gold standard treatment.

How useful is intraoperative cone beam computed tomography in maxillofacial surgery? An overview of the current literature.

Intraoperative imaging is increasingly used by surgeons and has become an integral part of many surgical procedures. This study was performed to provide an overview of the current literature on the intraoperative use of cone beam computed tomography (CBCT) imaging in maxillofacial surgery. A bibliographic search of PubMed was conducted in March 2020, without time limitation, using "intraoperative imaging" AND "maxillofacial surgery" AND "cone beam computed tomography" as key words. Ninety-one articles were found; after complete reading, 16 articles met the eligibility criteria and were analysed. The results showed that the majority of the indications were related to maxillofacial trauma, particularly zygomaticomaxillary complex fractures. Final verification with intraoperative CBCT before wound closure was the most common use of this device. However, innovative uses of intraoperative CBCT are expanding, such as CBCT coupling with mirror computational planning, and even the combined use of initial intraoperative CBCT acquisition with navigation. Immediate, fast, and easy evaluation of bone repositioning to avoid the need for further surgical revision is the main advantage of this technique. Imaging quality is comparable to that of multi-slice computed tomography, but with lower radiation exposure. Nevertheless, CBCT is still not widely available in maxillofacial centres, probably because of its cost, and perhaps because not everyone is aware of its advantages and versatility, which are reported in this review.

The role of the transversal ligament on the atlantoaxial complex - Bending forces at C1/2 flexion limits in the elderly.

INTRODUCTION: Biomechanical functionality as well as trauma mechanisms of the atlantoaxial complex are still an issue of controversy. The transverse atlantal ligament is the strongest stabilizator. The present study aimed to analyze the bending forces of the transverse atlantal ligament and of the base of the odontoid in elderly specimens. METHODS: In this biomechanical study five cadaveric specimen with a mean age of 72 at death and bone mineral density measuring for 555.3 Hounsfield units on average were used. To analyze the strain of the transverse atlantal ligament and the dense base, strain gauges were used. A custom biomechanical setup was used to test each specimen at C1/2 flexion and the strain of the transverse atlantal ligament and the dens base (µm/m) were measured. FINDINGS: In four out of five, a rupture of the transverse atlantal ligament was observed, the mean force required for the ligament to fall was 175 N (min. 99.8 N; 249.2 N; SD 64.7) by a mean strain of 2102.9 µm/m (min. 1953.5 µm/m; max. 2272.3 µm/m; SD 189.7). In one specimen with the lowest Hounsfield units (155), the dens base fractured before the transverse atlantal ligament ruptured and no strain could be measured at the transversal ligament during movement afterwards. INTERPRETATION: The transverse atlantal ligament fails at an average of 175 N in the elderly, which is less than the value reported previously. In osteoporotic specimen the generated force to rupture the transverse atlantal ligament can fracture the dens itself.

Surgical approach of ectopic maxillary third molar avulsion: Systematic review and meta-analysis.

Ectopic maxillary third molars (EMTM) are extracted mainly by the Caldwell-Luc technique but also by nasal endoscopy. There is currently no consensus on the treatment of this eruption and its management is heterogeneous and multidisciplinary. Two literature searches were performed with no time restrictions via Pubmed. In the first, we used the keywords "ectopic AND third molar" and in the second the keywords "dentigerous cyst AND ectopic third molar". For both articles, epidemiological, symptomatic, radiological and surgical data were recorded. Overall, 33 eligible articles were identified involving 39 cases of EMTM. 79% of patients were symptomatic. 87% of the teeth were associated with a dental cyst. In only 13% of cases was the location of the tooth in the sinus specified in the three planes of the space. Surgery was performed in 77% of patients by the Caldwell-Luc technique, by nasal endoscopy in 10% and by the Le Fort I approach in 3%. The indications for avulsion of EMTM are symptomatic patients or asymptomatic patients with an associated cyst. The intra-sinusal location of the tooth is not a factor in the choice of technique used, which depends rather on the individual skills of the surgeon. Although for a trained operator the Le Fort I osteotomy is an easy procedure, its interest in the treatment of EMTM is limited owing to the rare but potentially severe complications involved.

[Mechanical properties of collagen membranes used in guided bone regeneration: a comparative study of three models]. / Propriétés mécaniques des membranes de collagène.

OBJECTIVES: The peroperative rupture of a collagen membrane is a potential cause of complications and loss of effectiveness. The purpose of our study was to determine experimentally the mechanical properties (Young modulus, stress-strain curve, tensile strength) of three collagen membranes used in guided bone regeneration. These properties and isotropy were compared on dry and damp samples. METHODS: Standardized samples were tailored in three different membranes (Biomend Extend(®) [Zimmer Dental™], Bio-Gide(®) [Geitslich™] Neonem(®) [TBR™]) in two orthogonal orientations. They were then anchored on an ElectroForce(®) 3230 Instrument (Bose™) traction machine in a dry and wet state (soaking during 10 minutes in saline at 37°C). The strain curves were analyzed to obtain the various mechanical values. RESULTS: No anisotropy was observed. The Biomend Extend(®) membranes were significantly more resistant in dry and damp states than others. DISCUSSION: The mechanical properties of collagen membranes are very different from one to another. Moistening of the membranes, unavoidable in vivo, considerably alters their mechanical properties. This data should be taken into consideration when choosing a membrane.

Gingival Mucosa-Associated Lymphoid Tissue (MALT) lymphoma developed around a mandibular extraosseous dental root canal overfilling: A case report.

Lymphomas are rare pathologies in the oral cavity, representing only 3.5% of malignant tumors. Their typical topography is Waldeyer's lymphatic ring and approximately 8% of all non-Hodgkin lymphomas are mucosa associated lymphoid tissue (MALT) lymphomas. The authors report a rare case of mandibular gingival MALT lymphoma, which developed around an extraosseous dental root canal overfill. This atypical, case of lymphoma indicates that practitioners have to be vigilant and perform a biopsy every time they are confronted with a suspicious chronic lesion in the oral cavity.

The high sub-mandibular approach: Our experience about 496 procedures.

INTRODUCTION: The potential drawbacks of surgical approaches to neck and base fractures of the mandibular condyle (visible scare, facial nerve injury) are still considered by many surgeons as a brake for open reduction and internal fixation. The aim of our study was to analyze the results in terms of access, scare quality and complications that could be noticed in a 12 years period of time with the use of the high sub-mandibular approach (HSMA) we first described in 2006 for the surgical treatment of neck and base fractures. MATERIAL AND METHOD: All the files of patients operated on for condylar neck and base fractures approached by mean of a HSMA between January 2006 and December 2018 in our department and containing information concerning age, sex, type of fracture, kind of osteosynthesis material, operating time, name of the surgeon, postoperative complication linked to the approach, scare quality at 6 months follow-up at least were included. The skin incision and the dissection planes followed the original publication of Meyer et al. in 2006. RESULTS: 434 patients (sex ratio: 2.06, mean age: 32, 496 approaches) met the inclusion criteria. Following the AO classification, 21.2% of the fractures were classified as neck fractures and 78.8% as base fractures. 97.6% of all fractures were stabilized by mean of a 3D plate (TCP® plate, Medartis, Basel-CH), the remaining ones by mean of a combination of 1.2, 1.5 and 2.0 straight plates. Mean operating time was 40minutes per side. Patients were operated on by senior surgeons in 71.7% of the cases and by trainees under supervision for the others. Concerning the complications linked to the approach, we noticed 11 (2.2%) temporary (0 definitive) paresis of the facial nerve, 1 (0.2%) hematoma and 1 (0.2%) abscess that both needed revision. Scare was hypertrophic or considered as unaesthetic by the patient in 5 cases (1%). DISCUSSION: The HSMA, if performed as initially described, is a safe and quick procedure compared to other cutaneous approaches. It gives access to all base fractures and to most of neck fractures. The very low rate of facial nerve complications is mainly explained by the plane by plane dissection making it very easy to avoid the facial nerve branches or to check them when encountered. The HSMA is particularly suited to the use of TCP plates as the upper holes of these plates, placed horizontally, are easy to reach from below. The HSMA is therefore still our preferred cutaneous approach to the condylar process.

Customized three-dimensionally printed mandibular external fixator.

The advent of customized three-dimensional (3D) printing allows the affordable manufacturing of sophisticated medical devices, thereby providing swift and simple solutions to specific needs in modern healthcare. Meanwhile, certain devices such as industrial mandibular external fixators (EFs) have become less and less available from medical device companies because of decreased indications. What is more, their handling is often complex. The authors report, step by step, the original design and uneventful clinical use of a 3D-printed, customized mandibular EF. This device was designed together with a positioning and drilling guide for the fixation of a septic mandibular pseudarthrosis. It provided an adequate and satisfactory balance between lightness and rigidity. A simple, accurate and safe placement of the EF was achieved thanks to the skin-supported positioner and drilling guide, thereby making the procedure minimally invasive and time-efficient. To our knowledge, this is the first reported clinical use of a 3D-printed, customized mandibular EF to date. Because such 3D technology is becoming increasingly available to a large number of surgeons, the authors believe that the present innovation could become an alternative to reusable standard EFs.

[Massive sinus-lift procedures with beta-tricalcium phosphate: long-term results]. / Greffes sinusiennes massives par phosphate tricalcique. Résultats à long terme.

INTRODUCTION: The use of bone substitutes in massive sinus-lift pre-implant procedures remains controversial. The aim of our study was to evaluate the long-term reliability of pure-phase beta-tricalcium phosphate (betaTCP, Cerasorb, Curasan, Kleinostheim, Germany) used in this particular indication. MATERIAL AND METHOD: Twenty patients (33sinus) presenting with severe sinus floor atrophy (class 4 to 6 according to Cawood) and having undergone a sinus lift procedure by mean of betaTCP were followed in a prospective study between January 2002 and May 2008. The surgical approach was classical (under local anesthesia in eight patients) and the sinuses were filled with betaTCP (6 cm3 on average per sinus) and autologous growth factors (platelet rich plasma PRP and platelet rich fibrin PRF, according to the technique described by Dohan and Weibrich). One hundred and twenty-three dental implants were inserted in the grafted sinuses between the fourth and the eighth postoperative month (Nobel Biocare MK III and MK IV-mean length: 12.44 mm) using a 2-step buried technique and loaded between the fourth and the sixth month. Follow-up included regular clinical examination and panoramic X-rays to screen for possible sinus and implant complications. The control X-rays also allowed measuring the biomaterial resorption rate. RESULTS: The mean postoperative follow-up was 4.5 years for the sinus lift procedures and 4 years for the implants. We noted one case of local infection at the 15th postoperative day (3%). The implant success rate was 97.6% (lack of osteo-integration for two implants in the same patient, one failure after loading). The prosthetic success rate was 100%. The mean resorption rate of the material was 20.3% and the mean gain of height was 16.9 mm. DISCUSSION: The use of betaTCP associated to growth factors (PRP ou PRF) without bone graft, in massive sinus-lift procedures induces few complications. The implant success rate is comparable to the one obtained by using autologous bone grafts. The resorption rate of the material is comparable to that of autologous bone.

Surgically assisted rapid palatal expansion in class III malocclusion: Our experience.

INTRODUCTION: Maxillary transverse deficiency (MTD) is a common facial disharmony that may need surgical assisted rapid palatal expansion (SARPE). The aim of this study was to present our SARPE technique and to report about our experience. MATERIEL AND METHOD: Medical records of all class III patients who underwent SARPE in our department from 2010 to 2015 and for whom a follow-up of at least 1year was available, were included in a retrospective study. The technique consisted, after short orthodontic preparation allowing for divergence of the upper central incisors, in a complete Le Fort I osteotomy without down fracture, and medial sagittal submucosal separation of the hard palate under general anesthesia in an inpatient procedure. Teeth-supported distracters were sealed preoperatively while bone-supported devices were inserted peroperatively. Activation of the distracter was allowed from day 2 at the rate of 2×0.25 per day during 4days and 2×0.5mm per day the following days. Distracters were left in place for about 4months. Orthodontic treatment resumption was allowed from the second month. The initial malocclusion, the amount and type (parallel or angular) of distraction that was needed, the type of distracter used, the amount of distraction obtained, the per- and postoperative complications and the clinical stability of the end result were analyzed. RESULTS: The records of 23 patients (18 women, 5 men - average age: 25.4years, extremes: 16-55years) could be included. MTD was isolated in 6 cases, associated with a maxillary retrognathism in 5 cases, with a mandibular prognathism in 6 cases, and with both in 6 cases. The average amount of distraction needed was 7.2mm (range: 4-12), parallel in 20 cases and angular in 3 cases. The distracters were bone-supported (Rapid Palatal Expander®, KLS Martin Group, Tuttlingen, Germany) in 3 patients and custom-made tooth-supported in 20 patients. The average amount of distraction obtained at the level of the distracter cylinder was 7.7mm (range: 5-13). We noted 2 cases of palatal fibromucosa perforations, 1 case of posterior excess of distraction, 1 case of nasal septum deviation, 1 case of iatrogenic necrosis of tooth No.°11, 1 case of naso-genial sulcus hematoma, 1 case of intraoperative mobility of tooth No.°21, 5 cases of asymmetric distraction. Seventeen patients needed a second orthognathic procedure and 22 had stable Class I occlusion after removal of appliances at 18 months follow-up on average. DISCUSSION: SARPE is a quite safe procedure that allows for transverse coordination without dental extraction. Transverse discrepancies greater than 4mm are for us clear indications for SARPE. When a sagittal discrepancy is associated, we prefer performing SARPE first and correcting the sagittal plane in a second operation. The recent development of Le Fort I sliding osteosynthesis plates opens the way to one time correction and the development of double-action distracters fitted out with 2 cylinders will be helpful for performing angular distractions.

[Consequences of impacted wisdom teeth extraction on the periodontal environment of second molars. A pilot study]. / Conséquences de l'avulsion des dents de sagesse incluses sur l'environnement parodontal des deuxièmes molaires. Une étude pilote.

INTRODUCTION: Wisdom teeth extraction is a common procedure, generally considered as safe by patients. However, complications are possible, especially periodontal ones. The aim of this study was to evaluate the frequency and the consequences of periodontal complications at the level the 2nd molars after extraction of the wisdom teeth. MATERIAL AND METHODS: A single-center retrospective observational multi-operator study was conducted at the university hospital of Besançon - France. The files of all the adult patients who underwent extraction of four impacted wisdom teeth by mean of a standardized surgical technique between November 2012 and November 2014 and who could be followed 1 year postoperatively at least and that precisely mentioned the periodontal status of the surgical sites were included. Postoperative complications, gingival and plaque indexes according to Loë and Silness, periodontal attachment level and periodontal second molar probing were recorded. The main judgment criterion was the occurrence of a periodontal complication in the second molar areas. RESULTS: The files of 20 patients (15 women - 5 men), operated on by five different surgeons, met the inclusion criteria. Two patients suffered from dry socket at one of the avulsion sites. No patient had a gingival or plaque index greater than 2. No gingival recession or periodontal pocket over 4mm was found. DISCUSSION: Extraction of impacted third molars in young healthy adults didn't have any impact on the second molars periodontal environment in our study. Literature suggests that surgical technique greatly influences the occurrence and the extent of periodontal sequelae.

[Evaluation of healing time of osteochemonecrosis of the jaw after surgery: Single-center retrospective study and review of the literature]. / Évaluation des délais de guérison des ostéochimionécroses des maxillaires après traitement chirurgical : étude rétrospective monocentrique et revue de la littérature.

INTRODUCTION: Osteochemonecrosis of the jaw (ONJ) is a chronic ischemic bone exposure. It has an increasing incidence. ONJ is mainly related to bisphosphonate and denosumab therapies in oncologic settings. Healing is considered uncertain ad as occurring slowly. International recommendations suggest to treat ONJ symptomatically in a first attempt. A surgical procedure, potentially aggressive, should be carefully weight up in patients in poor condition and whose life expectancy is often limited. However, surgical treatment seems to allow for a high rate of clinical remission. Postoperative remission periods, when mentioned in the studies, are disparate. The aim of our study was to clarify the remission period of ONJ after surgical management. METHOD: A retrospective study was conducted on all patients operated for an ONJ at stage 2 and 3 in the Department for Oral and Maxillofacial Surgery - University Hospital of Besançon (France) from January 2006 to September 2015. Healing was defined as complete mucosal closure and asymptomatic site. Stage of the disease, the number and the type of surgery and the time between the last operation and the healing was noticed. These data were compared to an exhaustive review of the literature on PubMed with the following key-words: "osteonecrosis" AND "jaw" AND "surgery" AND "management". Only the articles giving the healing period were included. RESULTS: Regarding the single-center retrospective study, the files of 23 patients could be included. Fifteen percent of the patients benefited from several procedures under general anesthesia. Twenty percent had a stage 3 ONJ and 80 % had a stage 2 ONJ. Twenty-five interventions were performed on 23 sites in 20 patients. Immediate healing after surgery occurred in 35 % of the patients. At 6 months after surgery, 57 % of the treated areas were healed. Twenty percent of the patients had died. The healing rate did not improve further after 6 months postoperatively. Regarding the review of the literature, 7 articles could be included. The mean postoperative healing period was 60.7 % at 6 months, 71.1 % at 12 months and 69.5 % at 18 months. DISCUSSION: Our study shows that the postoperative healing rate of ONJ lies between 57 and 66.7 % at 6 months and that this rate was optimized in the order of 10 % to 12months and stable at 18months postoperatively. The ONJ of our series were partially or fully linked to other drugs than bisphosphonates in 70 % of the cases: 50 % were related to denosumab, alone or in combination and 35 % were related to an association with antiangiogenics, bevacizumab mainly.

How useful is 3D printing in maxillofacial surgery?

INTRODUCTION: 3D printing seems to have more and more applications in maxillofacial surgery (MFS), particularly since the release on the market of general use 3D printers several years ago. The aim of our study was to answer 4 questions: 1. Who uses 3D printing in MFS and is it routine or not? 2. What are the main clinical indications for 3D printing in MFS and what are the kinds of objects that are used? 3. Are these objects printed by an official medical device (MD) manufacturer or made directly within the department or the lab? 4. What are the advantages and drawbacks? METHODOLOGY: Two bibliographic researches were conducted on January the 1st, 2017 in PubMed, without time limitation, using "maxillofacial surgery" AND "3D printing" for the first and for the second "maxillofacial surgery" AND "computer-aided design" AND "computer-aided manufacturing" as keywords. Articles in English or French dealing with human clinical use of 3D printing were selected. Publication date, nationality of the authors, number of patients treated, clinical indication(s), type of printed object(s), type of printing (lab/hospital-made or professional/industry) and advantages/drawbacks were recorded. RESULTS: Two hundred and ninety-seven articles from 35 countries met the criteria. The most represented country was the People's Republic of China (16% of the articles). A total of 2889 patients (10 per article on average) benefited from 3D printed objects. The most frequent clinical indications were dental implant surgery and mandibular reconstruction. The most frequently printed objects were surgical guides and anatomic models. Forty-five percent of the prints were professional. The main advantages were improvement in precision and reduction of surgical time. The main disadvantages were the cost of the objects and the manufacturing period when printed by the industry. DISCUSSION: The arrival on the market of low-cost printers has increased the use of 3D printing in MFS. Anatomic models are not considered to be MDs and do not have to follow any regulation. Nowadays, they are easily printed with low-cost printers. They allow for better preoperative planning and training for the procedures and for pre-shaping of plates. Occlusal splints and surgical guides are intended for the smooth transfer of planning to the operating room. They are considered to be MDs and even if they are easy to print, they have to follow the regulations applying to MDs. Patient specific implants (custom-made plates and skeletal reconstruction modules) are much more demanding objects and their manufacturing remains nowadays in the hands of the industry. The main limitation of in-hospital 3D printing is the restrictive regulations applying to MDs. The main limitations of professional 3D printing are the cost and the lead time. 3D printed objects are nowadays easily available in MFS. However, they will never replace a surgeon's skill and should only be considered as useful tools.