[Piezoelectric osteotomy: applications in periodontal and implant surgery]. / L'ostéotomie piézoélectrique: applications en chirurgie parodontale et implantaire.

Reverse piezoelectricity is currently used in Dentistry for ultrasonic scaling devices. Using this technology, increasingly more powerful ultrasonic surgical lancets were developed within a few years, and these new tools have provided many practical solutions in oral and maxillofacial surgery. This article reviews the basic principles of piezosurgery, and its numerous clinical applications: in oral surgery (atraumatic extractions, wisdom teeth exposure, periapical cyst debridement, pre-prosthetic surgery), more specifically in periodontal (root planning and bone remodeling, crown lengthening) and implant surgery (sinus lift, removal of fractured implants, bone ridge augmentation, bone graft harvesting (crestal, retromolar, chin or tori)). The recent increased power of these instruments allows emphasizing a much wider range of clinical applications, extending to all surgical fields.

[Rationale for a fixed implant-supported transitional prosthesis in full-arch implant restorations]. / De l'importance de la prothèse transitoire implantoportée fixée au cours des réhabilitations implantaires complètes.

The use of a fixed transitional prosthesis in implantology remains quite seldom, although the concept of temporization and progressive loading of prosthetic restorations has become a main issue in modern dentistry. Fixed tansitional prostheses play an important role in the validation of full-arch implant-supported restorations, and in the success of implant treatments in general. This paper reviews the basic treatment principles, and discusses the different technical options available to the clinician. In simple cases, a hard resin bridge may be sufficient. However, for complex cases, we should better use fixed implant-supported temporary prosthesis, made in resin on a metallic infrastructure. Moreover, this one could be use as the framework of the permanent prosthesis. This technical solution offers the best guaranty for implant and oral rehabilitation validation before the permanent prosthesis installation.

[Influence of platelet rich fibrin (PRF) on proliferation of human preadipocytes and tympanic keratinocytes: A new opportunity in facial lipostructure (Coleman's technique) and tympanoplasty?]. / De l'influence du platelet rich fibrin (PRF) sur la prolifération des préadipocytes et keratinocytes tympaniques humains: une nouvelle opportunité pour la lipostructure faciale (technique de Coleman) et la tympanoplastie?

AIM: To analyze the effects of PRF (a platelet and immune autologous concentrate) on in vitro proliferation of human keratinocytes and preadipocytes, and to determine if these results may offer an opening on new clinical investigations, particularly in the improvement of tympanoplasties and facial lipostructures (Coleman's technique). MATERIALS AND METHODS: Human tympanic keratinocytes and preadipocytes are collected and cultured using the explant technique. 4 series of each type of cells are cultivated either in normal condition (control group) or with PRF (test group). The Petri dishes (of culture) are taken out on the 3rd, 7th, 14th and 21st day, for counting. Evolutions of cells' number are analyzed with a variance test. RESULTS: The number of cells in culture increases of more than 60% on the 7th day, and of almost 150% right from the 14th day when in presence of PRF. The daily proliferation peak occurs around the 14th day. The two cellular tested types react similarly. CONCLUSION: The PRF, considered as a healing biomaterial, could be used in tympanic and facial lipostructures surgeries, in order to improve the therapeutic result. Other applications in microsurgery and in plastic surgery may be possible, but specific clinical studies need to validate such protocols.

[The relevance of Choukroun's platelet rich fibrin (PRF) during facial aesthetic lipostructure (Coleman's technique): preliminary results]. / De l'intérêt du platelet rich fibrin (PRF) de Choukroun au cours de la lipostructure faciale esthétique de Coleman: résultats préliminaires.

OBJECTIVES: To evaluate the interest of fibrin PRF clots, a concentrate of platelets and immune factors, for the optimization of the adipocyte graft according to the technique of facial lipostructure described by S. Coleman. MATERIALS AND METHODS: Between May 2005 and June 2006, 32 patients (7 men and 25 women) benefited from a Coleman lipostructure with the use of PRF. The average age was 59 years (39 to 72 years). Lipostructure was used alone in 22 patients and associated with a face lift and/or a blepharoplasty in 10 patients. Before the adipocyte graft, a mixture of PRF and greasy supernatant (resulting from the purification of the sample of adipocytes) is deposited on the zones to be grafted in the same way as for lipostructure. For 2 patients, the pretreatment of the site to be grafted with PRF was unilateral. Patients were followed-up for one year. RESULTS: In this series, all the patients were satisfied with the result with minimal associated resorptions. No massive resorption requiring a resumption of lipostructure was noted. In the 2 patients treated with unilateral use of PRF, one notes a light asymmetry, the hemi-face treated with PRF appearing more stable than the side without PRF. No important residual oedema or echymosis were seen on the 3rd post-operative week. CONCLUSION: By offering a matricial support to angiogenesis and by stimulating the proliferation of pre-adipocytes, the PRF could have a beneficial role on the cicatrization and the consolidation of an adipocyte graft. Further studies are necessary to validate the interest of the PRF during aesthetic lipostructures. The potential uses in plastic surgery of such a biomaterial, easy and fast to produce, without any overcost and with no risk, are very numerous and require from now on to be tested and validated methodically.

Possible involvement of gelatinase A (MMP2) and gelatinase B (MMP9) in toxic epidermal necrolysis or Stevens-Johnson syndrome.

Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) are considered to be drug-induced diseases, and are characterized by extensive mucocutaneous disorder and epidermal necrosis which result in the detachment of the epidermis. Inactive and active forms of metalloproteinases (MMP2 and MMP9) secreted by skin explants maintained in organ culture for 72 h and in blister fluid from two TEN and three SJS patients were investigated. Interestingly, lesional skin from both the TEN and the SJS patients cultured for 3 days in conditioned medium showed high levels of both 72 kDa progelatinase A and 66 kDa activated gelatinase A, and the 66 kDa activated form was not observed in cultures of skin from control individuals. Furthermore, indirect immunodetection showed the presence of MMP2 and MMP9 in TEN and SJS patients' skin. Increased gelatinase activity in the culture medium of TEN and SJS skin maintained in organ culture and in blister fluid indicates that these gelatinases may be responsible for the detachment of the epidermis in these drug-induced necrolyses.

Magnetic resonance imaging use by primary care physicians.

BACKGROUND: Magnetic resonance imaging (MRI) has recently been introduced in the United States as an imaging technique for clinical use. Initially used by neurologists to view the brain stem, its indications have rapidly expanded to include spine, pelvis, bone marrow, and joints. This has raised concerns over the appropriate, cost-effective use of such an expensive technology. This paper examines MRI scanning patterns that have developed over time in central Massachusetts and surveys primary care knowledge, attitudes, and patterns of utilization. METHODS: The two MRI centers in central Massachusetts were surveyed for information about the number and types of scans ordered and the specialties of the physicians who ordered the scans. Questionnaires were sent to primary care physicians in Worcester County to assess knowledge and attitudes about MRI and utilization. RESULTS: The data demonstrate changing patterns of MRI utilization over time. Orthopedics has been the specialty with the greatest increase in use, now slightly surpassing neurology in the total number of scans ordered. Primary care physician use has doubled over this same period. Not all primary care physicians utilize MRI, but those who have used the technology have familiarized themselves with its indications and problems and have a better knowledge about its costs. CONCLUSIONS: Utilization patterns of MRI have changed considerably in a short time, with primary care physicians requesting use of this new technology much more frequently than when it was first introduced.