Alveolar corticotomies for accelerated orthodontics: A new mini-invasive technique.

Orthodontic and surgical techniques are constantly evolving and practitioners are facing an increasing demand for shorter treatments, with an expectation of results equivalent to conventional treatments. Corticotomies have made it possible to partly meet this need by facilitating dental movement in adult orthodontic care. Many surgical corticotomy techniques were proposed in the past presenting advantages but also a certain number of disadvantages. After retracing the various surgical techniques proposed and explaining the biological principles, we will introduce a new minimally invasive technique, without mucoperiosteal flap and without piezosurgery. This technique can be performed in the dental chair under local anaesthesia or sedation. It is simple and reproducible. This type of treatment combines comfort, speed and periodontal protection. Our objective is to provide more patients and practitioners with corticotomies while controlling the benefit/risk ratio.

Three-dimensional imaging control of osteogenesis induced by minimally invasive corticotomies: Perspectives from a case report.

Corticotomies are now an integral part of the orthodontist's therapeutic arsenal in adult orthodontics. In recent years, the number of publications about different surgical techniques has increased significantly. This shows that practitioners and patients have a common interest. It is now accepted that corticotomies cause a regional acceleratory phenomenon, which enables a faster dental movement, a reduction in treatment time, as well as a reduction in the risk of root resorption. The perspective of osteogenesis induced by corticotomies has already been mentioned in literature. It could provide a real advantage in maintaining the periodontium, reducing the risk of fenestration or dehiscence and the stability of long-term treatment by increasing the dental bone envelope. Through a clinical case, treated by mini- invasive surgical technique (as described in the previous article), we highlight the potential for osteogenesis induced by alveolar corticotomies and the utility of this procedure in adults.

[Micro-porous titanium implants in orthognathic facial recontouring]. / Corrections volumétriques du visage par implants en titane microporeux.

INTRODUCTION: Facial symmetry has always been a longstanding objective of orthognathic surgery. Patients that present significant facial asymmetry desire functional dental occlusion but also seek to enhance their facial esthetics. In that regard, different surgical techniques have been proposed to enhance facial recontouring. MATERIALS AND METHODS: Through a clinical case report and a literature review, this article explores the use of allopastic microporous titanium implants in volumetric corrections of the face. RESULTS: There is a current lack of evidence regarding the use of microporous titanium implants in volumetric corrections of the face, most papers reporting their use in post-traumatic or post-surgical cranio-facial defects repair. DISCUSSION: Pros and cons of such implants are discussed in association with the usefulness of this surgical technique in daily orthognathic surgical practice.

[Bone formation and corticotomy-induced accelerated bone remodeling: can alveolar corticotomy induce bone formation?]. / Formation osseuse et corticotomies à visée de facilitation métabolique : existe-t-il une ostéogénèse induite par les corticotomies alvéolaires ?

Current orthodontic treatments must answer an increasing demand for faster yet as efficient treatments, especially in adult patients. These past years, the amelioration of orthodontic, anesthetic and orthognathic surgery techniques have allowed considerable improvement of orthodontico-surgical treatments and of adult orthodontic treatments. Alveolar corticotomy (an example of such techniques) accelerates orthodontic tooth movements by local modifications of bone metabolism, inducing a transient osteopenia. This osteopenia allows greater tooth movements than conventional techniques. Whereas there is a growing understanding of the underlying biological mechanisms of alveolar corticotomies, there is little data regarding the osteogenic potential of such technique. In the present article, we review the literature pertaining to alveolar corticotomies and their underlying biological mechanisms and present a clinical case underlining the osteogenic potential of the technique.

[Orthognathic surgery in adults: state of the art]. / Données actuelles en chirurgie orthognathique de l'adulte.

The objective of orthognathic surgery is the repositioning of the osseous bases of the jaws. Its consequences are both aesthetic and functional. As adults are increasingly concerned with appearance, orthognathic surgery is today, more than ever, a close collaboration between the orthodontist, surgeon and general dentist. The whole team must be capable of coordinating its approach with an aesthetic objective. For the surgeon, a perfect knowledge of complementary techniques (rhinoplasty, bone grafts, plastic surgery of the face, lipostructure or fillers) makes orthognathic surgery a completely separate surgical speciality. The aim of this article is to establish the philosophy underlying this type of treatment and define relevant fundamental aspects. We propose an esthetic "extra-oral" clinical approach not focused on occlusal anomalies but on classification of tooth positional abnormalities in the smile and the therapeutic options that we have for placing teeth in correct positions in the smile.

Rehabilitation of congenital facial palsy with temporalis flap--case series and literature review.

BACKGROUND: Congenital facial paralysis is a rare disorder with an incidence of less than 1 in 1000 live births. Several surgical rehabilitation techniques have been described, such as free flaps or transpositions of the temporalis muscle. We report our experience of transposition of the temporalis muscle in this indication. MATERIALS AND METHODS: Retrospective monocentric study between January 2005 and December 2009. RESULTS: Five children (mean age at the surgery: 7.3 years, range 6-13) presenting with a congenital facial paralysis were treated by a temporalis muscle transposition during the considered period. An etiological assessment was achieved by carrying out a petrous bone CT, a cerebral and petrous MRI, and audiometric evaluation. Four patients out of 5 (80%) showed a satisfactory and stable functional outcome over time (average follow-up: 26 months). CONCLUSION: Temporalis muscle transposition is a single-stage procedure, easily adapted for the pediatric condition of congenital facial paralysis. It is our opinion that this procedure needs to be carried out at the end of the pre-school period.

Autologous fat transfer in velopharyngeal insufficiency: indications and results of a 25 procedures series.

OBJECTIVE: To assess the efficiency of autologous fat transfer (AFT/Coleman procedure) in the management of velopharyngeal insufficiency (VPI). SETTINGS: Tertiary academic center, retrospective case series over a 4 year period. Pre- and post-speech assessment by a speech pathologist using the Borel-Maisonny scale. PATIENTS AND METHOD: Twenty-five (25) procedures were performed on 22 patients during the considered period. Mean age at surgery was 12.4 ± 4.1 years-old. Main associated conditions were 22q11 deletion (n=6 including 2 with cleft palate), isolated cleft palate (n=3), and Robin sequence (n=2). Indications were VPI grade 2a (n=5), 2b (n=11) and 3 (n=6), despite prolonged speech therapy (pre-op mean duration: 4.2 years) and previous surgery (velopharyngoplasty, n=13). Four patients had a contraindication of velopharyngoplasty (aberrant internal carotid arteries). RESULTS AND CONCLUSION: Fat harvesting sites were umbilicus (n=23) and buttock (n=2). Mean injected fat volume was 7.8 ml, in the posterior wall of the pharynx (n=25) the soft palate (n=15), the peritonsillar arches (n=3), and the pre-existing flap (n=3). Mean follow-up was 17 months. Two patients relapsed once and one patient twice, requiring additional injections. Final post-operative examination 1 year after the last procedure showed an improvement of speech in 90% of cases (grade 1, n=2; 1/2a, n=5; 2a n=10; 2b, n=5). AFT is a safe technique indicated in the primary and secondary management of VPI, with stable results on speech. However, if a complete return to normal is difficult to achieve, its simplicity allows multiple procedures in the same patient.

Three-dimensional architecture and cell composition of a Choukroun's platelet-rich fibrin clot and membrane.

BACKGROUND: Platelet-rich fibrin (PRF; Choukroun's technique) is a second-generation platelet concentrate for surgical use. This easy protocol allows the production of leukocyte and platelet-rich fibrin clots and membranes starting from 10-ml blood samples. The purposes of this study were to determine the cell composition and three-dimensional organization of this autologous biomaterial and to evaluate the influence of different collection tubes (dry glass or glass-coated plastic tubes) and compression procedures (forcible or soft) on the final PRF-membrane architecture. METHODS: After centrifugation, blood analyses were performed on the residual waste plasmatic layers after collecting PRF clots. The PRF clots and membranes were processed for examination by light microscopy and scanning electron microscopy. RESULTS: Approximately 97% of the platelets and >50% of the leukocytes were concentrated in the PRF clot and showed a specific three-dimensional distribution, depending on the centrifugation forces. Platelets and fibrin formed large clusters of coagulation in the first millimeters of the membrane beyond the red blood cell base. The fibrin network was very mature and dense. Moreover, there was no significant difference in the PRF architecture between groups using the different tested collection tubes and compression techniques, even if these two parameters could have influenced the growth factor content and biologic matrix properties. CONCLUSIONS: The PRF protocol concentrated most platelets and leukocytes from a blood harvest into a single autologous fibrin biomaterial. This protocol offers reproducible results as long as the main production principles are respected.

Choukroun's platelet-rich fibrin (PRF) stimulates in vitro proliferation and differentiation of human oral bone mesenchymal stem cell in a dose-dependent way.

BACKGROUND: Choukroun's platelet-rich fibrin (PRF) is an autologous leukocyte- and platelet-rich fibrin biomaterial. The purpose of this study was to analyse the in vitro effects of PRF on human bone mesenchymal stem cells (BMSC), harvested in the oral cavity after preimplant endosteal stimulation. MATERIALS AND METHODS: BMSCs from primary cultures were cultivated with or without a PRF membrane originating from the same donor as for the cells, in proliferation or osteoblastic differentiation conditions. After 7 days, the PRF membranes were removed. A series of cultures were performed using 2 PRF membranes, in order to measure the dose-dependent effect. Cell counts, cytotoxicity tests, alkaline phosphatase (ALP) activity quantification, Von Kossa staining and mineralisation nodules counts were performed at 3, 7, 14, 21 and 28 days. A last independent series was carried on up to 14 days, for a morphological scanning electron microscope (SEM) observation. RESULTS: PRF generated a significant stimulation of the BMSC proliferation and differentiation throughout the experimental period. This effect was dose-dependent during the first weeks in normal conditions, and during the whole experimentation in differentiation conditions. The cultures without PRF in differentiation conditions did not rise above the degree of differentiation of the cultures in normal conditions with 1 or 2 PRF up to the 14th and 28th day, respectively. The SEM culture analysis at day 14 allowed to show the mineralisation nodules which were more numerous and more structured in the groups with PRF compared to the control groups. DISCUSSION AND CONCLUSIONS: This double contradictory proliferation/differentiation result may be due to the numerous components of PRF, particularly the presence of leukocytes: any culture with PRF is in fact a coculture with leukocytes. It could be the source of differential geographic regulation processes within the culture. The combination of oral BMSC and PRF might offer many potential clinical and biotechnological applications, and deserves new studies.

In vitro effects of Choukroun's PRF (platelet-rich fibrin) on human gingival fibroblasts, dermal prekeratinocytes, preadipocytes, and maxillofacial osteoblasts in primary cultures.

OBJECTIVES: The objective of this study was to analyze the effects of Choukroun's PRF (platelet-rich fibrin), a leucocyte and platelet concentrate clinically usable as fibrin membrane or clot, on human primary cultures of gingival fibroblasts, dermal prekeratinocytes, preadipocytes, and maxillofacial osteoblasts. STUDY DESIGN: For the proliferation study, these cells were cultivated with or without a PRF membrane originating from the same donor as for the cells. For osteoblasts and fibroblasts, dose-dependent effect was assessed (using 2 membranes). Cell counts and cytotoxicity tests were performed at 3, 7, 14, and 21 days, and even 28 days for osteoblasts. More osteoblast cultures were prepared in differentiation conditions according to 3 modalities (without PRF, with PRF, with PRF the first day and differentiation medium applied only after the first week of culture). Osteoblast differentiation was analyzed using Von Kossa staining and alkaline phosphatase, DNA and total cell proteins dosage. RESULTS: PRF induced a significant and continuous stimulation of proliferation in all cell types. It was dose dependent during all the experiment with osteoblasts, but only on day 14 with fibroblasts. Moreover, PRF induced a strong differentiation in the osteoblasts, whatever the culture conditions. The analysis of osteoblast cultures in differentiation conditions with PRF, using light and scanning electron microscopy, revealed a starting mineralization process in the PRF membrane itself after 14 days. Moreover, PRF leucocytes seemed to proliferate and interact with osteoblasts. CONCLUSIONS: Cultures with PRF are always cocultures with leucocytes. These "chaperone leucocytes" could be the source of differential geographic regulation within the culture and explain the double contradictory effect proliferation/differentiation observed on osteoblasts.

[Embryology of the face and oto-mandibular dysplasia]. / Embryologie de la face et dysplasies otomandibulaires.

Otomandibular dysplasias encompass a broad range of congenital malformations (hemifacial microsomia, mandibulofacial dysostosis) affecting both jaw and ear apparatus. Deciphering the mechanisms of normal embryonic development is a prerequisite for optimal clinical management of those malformations. The development of craniofacial structures is a multi-step process, which involves many developmental events ranging from the migration of neural crest cells from the neural primordium, the molecular interactions that coordinate outgrowth and patterning of the facial primordia, to the fine tuning of the skeletal components. Our knowledge concerning craniofacial development has been gain through experiments carried out in animal developmental models; cell tracing strategies and functional analyses have contributed to significantly increment our understanding of human otomandibular dysplasias. In this review, we discuss classical and recent aspects of otomandibular development. Current proposals for pathogenesis are reviewed and a clinical approach for mandibulofacial dysostosis is proposed.

Congenital isolated midline sinus of the upper lip: clinical and embryological approaches.

OBJECTIVES: Congenital sinuses or fistulas of the lip are uncommon malformations, yet true medial upper-lip fistulas (MULFs) are extremely rare. We present a new case of congenital upper-lip fistula located in the midline of the philtrum of an 8-month-old girl. INTERVENTION: Complete surgical removal was performed with a combined extra- and intraoral approach. Histological examination revealed that the fistula was lined by squamous epithelium with sebaceous and mucous glands and hair follicles. RESULTS: Several embryological hypotheses have been proposed concerning these anomalies. This article reexamines and discusses major embryological theories on pathogenesis of sinuses or fistulas of the upper lip. We propose that early ectodermal inclusion events may occur in the medial fusion area during formation of the intermaxillary process. This embryological approach is highly concordant with our recent hypothesis on nasal dermoid sinus cysts (NDSCs) pathogenesis, in which we proposed an embryological hypothesis with early ectodermal inclusion phenomenon in the midline suture area to explain NDSCs pathogenesis. CONCLUSIONS: Common early ectodermal inclusion phenomena could be involved in both NDSCs and MULFs pathogenesis.

Cellular dynamics and molecular control of the development of organizer-derived cells in quail-chick chimeras.

Malformations affecting the nervous system in humans are numerous and various in etiology. Many are due to genetic deficiencies or mechanical accidents occurring at early stages of development. It is thus of interest to reproduce such human malformations in animal models. The avian embryo is particularly suitable for researching the role of morphogenetic movements and genetic signaling during early neurogenesis. The last ten years of research with Nicole Le Douarin in the Nogent Institut have brought answers to questions formulated by Etienne Wolff at the beginning of his career, by showing that Hensen's node, the avian organizer, is at the source of all the midline cells of the embryo and ensures cell survival, growth and differentiation of neural and mesodermal tissues.

Craniofacial dermoids: an embryological theory unifying nasal dermoid sinus cysts.

OBJECTIVE: The nasal dermoid sinus cyst (NDSC) is an uncommon congenital lesion presenting as a large panel of midline craniofacial anomalies. The objective of this study was to review and reanalyze embryological hypotheses concerning NDSCs and to propose an embryological theory unifying the various anatomical characteristics of these lesions. The first case of frontal localization of a NDSC extending within the diploetic bone in a 9-month-old boy, presenting as a median frontal fistula with recurrent frontal swelling, 6 months after a mild frontal trauma is presented. RESULTS: Complete surgical removal was performed, and there was no evidence of either persistent or recurrent disease 2 years after his surgery. The embryological and anatomical origins of NDSCs are reviewed. This article reexamines and discusses major embryological theories on NDSC pathogenesis and proposes to refute the "prenasal space" theory of Grunwald and rehabilitate a forgotten embryological hypothesis, which unifies the main various clinical presentations of NDSCs.

Obstructive congenital gingival granular cell tumor.

Congenital gingival granular cell tumors (also known as congenital epulis or Neumann's tumor) are rare and always benign intraoral tumors originating from the alveolar ridge. They are typically seen as a mass protruding out of a newborn child's mouth. We report a case of a large obstructive congenital gingival granular cell tumor of the mandibular ridge. The intraoral mass was first detected on a 38-week prenatal ultrasound scan and resulted in neonatal airway obstruction. Complete surgical removal was performed with an uneventful postoperative course. Histologic and immunohistochemical assessments with antibodies against S-100 protein confirmed the diagnosis. The clinical and morphological aspects, differential diagnosis, histogenesis, and treatment are discussed.

Dual origin of the floor plate in the avian embryo.

Molecular analysis carried out on quail-chick chimeras, in which quail Hensen's node was substituted for its chick counterpart at the five- to six-somite stage (ss), showed that the floor plate of the avian neural tube is composed of distinct areas: (1) a median one (medial floor plate or MFP) derived from Hensen's node and characterised by the same gene expression pattern as the node cells (i.e. expression of HNF3beta and Shh to the exclusion of genes early expressed in the neural ectoderm such as CSox1); and (2) lateral regions that are differentiated from the neuralised ectoderm (CSox1 positive) and form the lateral floor plate (LFP). LFP cells are induced by the MFP to express HNF3beta transiently, Shh continuously and other floor-plate characteristic genes such as NETRIN: In contrast to MFP cells, LFP cells also express neural markers such as Nkx2.2 and Sim1. This pattern of avian floor-plate development presents some similarities to floor-plate formation in zebrafish embryos. We also demonstrate that, although MFP and LFP have different embryonic origins in normal development, one can experimentally obtain a complete floor plate in the neural epithelium by the inductive action of either a notochord or a MFP. The competence of the neuroepithelium to respond to notochord or MFP signals is restricted to a short time window, as only the posterior-most region of the neural plate of embryos younger than 15 ss is able to differentiate a complete floor plate comprising MFP and LFP. Moreover, MFP differentiation requires between 4 and 5 days of exposure to the inducing tissues. Under the same conditions LFP and SHH-producing cells only induce LFP-type cells. These results show that the capacity to induce a complete floor plate is restricted to node-derived tissues and probably involves a still unknown factor that is not SHH, the latter being able to induce only LFP characteristics in neuralised epithelium.