Early mandibular canine-lateral incisor transposition: case report

Purpose. The main aim of the present study is to present a case of mandibular transposition between lateral incisor and canine in a paediatric patient. Materials and methods. A fixed multibracket orthodontic treatment was performed by means of a modified welded arch as to correct the transposition and obtaining a class I functional and symmetrical occlusion, also thanks to the early diagnosis of the eruption anomaly. Results. Our case report shows that a satisfactory treatment of mandibular transpositions is obtained when detected at an early stage of the tooth development. Conclusions. The main treatment options to be taken into consideration in case of a mandibular transposition are two: correcting the transposition or aligning it leaving the dental elements in their transposed order; in both cases, the followups show a stable condition, maintained without relapses. Several factors, such as age of the patient, occlusion, aesthetics, patient’s collaboration, periodontal support and duration of treatment have to be considered as to prevent potential damage to dental elements and support appliances. The choice between the two treatment approaches for mandibular lateral incisor/canine transpositions mainly depends on the time the anomaly is detected

Two-to-one resonant multi-modal dynamics of horizontal/inclined cables. Part I : theoretical formulation and model validation

This paper is first of the two papers dealingwith analytical investigation of resonant multimodal dynamics due to 2:1 internal resonances in the finite-amplitude free vibrations of horizontal/inclined cables. Part I deals with theoretical formulation and validation of the general cable model. Approximate nonlinear partial differential equations of 3-D coupled motion of small sagged cables - which account for both spatio-temporal variation of nonlinear dynamic tension and system asymmetry due to inclined sagged configurations - are presented. A multidimensional Galerkin expansion of the solution ofnonplanar/planar motion is performed, yielding a complete set of system quadratic/cubic coefficients. With the aim of parametrically studying the behavior of horizontal/inclined cables in Part II [25], a second-order asymptotic analysis under planar 2:1 resonance is accomplished by the method of multiple scales. On accounting for higher-order effectsof quadratic/cubic nonlinearities, approximate closed form solutions of nonlinear amplitudes, frequencies and dynamic configurations of resonant nonlinear normal modes reveal the dependence of cable response on resonant/nonresonant modal contributions. Depending on simplifying kinematic modeling and assigned system parameters, approximate horizontal/inclined cable models are thoroughly validated by numerically evaluating statics and non-planar/planar linear/non-linear dynamics against those of the exact model. Moreover, the modal coupling role and contribution of system longitudinal dynamics are discussed for horizontal cables, showing some meaningful effects due to kinematic condensation

M.I.D. Atlas: a new systematic for the stabilization of removable prosthesis

Introduction: M.I.D. (mini dental implants) Atlas endosseous implants are single-phase titanium alloy Grade 5 with variable diameter (1,8-2,2-2,4 mm), so that they can be used even in severe bone atrophies. The entry is performed in the interforaminale area with flapless tecnique.The main indication is the stabilization of lower overdentures, very unstable due to various factors such us movements of the tongue and transverse and vertical bone atrophy in the presence of D1 or D2 bone density. M.I.D. for overdenture can be of two types: mini implants with metal ring with a Teflon cap to be fixed in the prosthesis and mini-implants with a ball held in a soft silicone (Tuf-Link) positioned in the undercut run directly in removable dentures (Atlas, Dentatus). Case report: Male patient, aged 56, carrier of lower total dentures has a severe mandibular bone atrophy with excessive instability of the prosthetis. After careful clinical and radiographic assessment, we proceeded to the insertion of Atlas 4 MID 2.4 mm in diameter with flapless technique. The excellent primary stability has allowed the immediate loading of implants by applying the silicone retentive "Tuf-Link " in removal denture. Control at 12 months shows the stability of the prosthesis, the successful osteintegration and the integrity of implants due to the careful management of occlusal loads. Conclusions: Implant System Atlas Implant System has proven to be a microinvasive, atraumatic, reliable and highly predictabl

Odontomas in developmental age: confocal laser scanning microscopy analysis of a case.

BACKGROUND: Odontomas are the most common benign odontogenic tumors (especially in children and adolescents) and consist of odontogenic ectomesenchyma and odontogenic epithelium with the formation of dental hard tissues. They are also simply considered hamartomas. The WHO Classification defines them as complex and compound odontomas. The diagnosis is often occasional, in conjunction with x-ray routine examinations, or it is suggested by eruption disorders or abnormal position of teeth in the dental arch. The mainstay therapy is surgical excision of the lesion followed by orthodontic treatment to take in the arch the impacted teeth. CASE REPORT: The aim of this work is the presentation of a case of mandibular bilateral compound odontoma in a young patient, and the confocal laser scanning microscopic analysis of the surgical specimens

Mandibular bilateral compound odontoma: histological and morphostructural features by confocal laser scanning microscopy

Objectives. Odontomas are the most common odontogenic tumors of the oral cavity. They account for 22-67% of all maxillary tumors with an increased prevalence in children and adolescents. They are asymptomatic and are generally diagnosed by radiographic examination. The chosen treatment is surgical excision of the lesion followed by a histo- pathological examination. The aim of this study is to show confocal laser scanning microscopic features in a case of compound odontoma not easily evident when using an optical traditional microscopy. Methods. A case of bilateral mandibular compound odontoma in young patient is presented. Radiographic analysis revealed two symmetrical radio-opaque masses with a surrounding thin radio-transparent halo, up to the first lower premolars. Surgical excision of the lesion under general anesthesia was performed. The specimens were fixed in a buffered solution of 10% formalin, embedded in paraffin, cut in 3 μm thick serial sections, stained with hematoxylineosin, observed by optical microscope and by Confocal Laser Scanning Microscope (CLSM). Results. Control at 2 weeks showed excellent healing of the tissues. Follow-up at 6 months showed the absence of recurrence and the eruption of the previously retained teeth. CLSM analysis in autofluorescence underlined a different fluorescence of soft and hard tissues showing different intensity of emission in autofluorescence due to different degrees of calcification. The odontogenetic components appeared strongly autofluorescent and presented foci of ectomesenchymal dentinogenetic multifocal differentiation that cause irregularities in the shape and structure of the tissue. Conclusions. Odontomas are frequent in childhood and are often responsible for dental retention. CLSM allows a careful histo-morphological analysis of odontomas and other odontogenic tumors. The morpho-structural organization of the cellular component is also observed with the possibility of three-dimensional reconstruction. References • Crincoli V, Scivetti M, Di Bisceglie MB, Lucchese A, Favia G. Complex odontoma: confocal laser scanning microscopy analysis of a case. Minerva Stomatol. 2007 Nov-Dec;56(11-12):611-20. • Da Silva LF, David L, Ribeiro D, Felino A. Odontomas: a clinico-pathologic study in a Portuguese population. Quintessence Int 2009; 40(1):61-72. • Tamme T, Soots M, Kulla A, Karu K, Hanstein S-M, Sokk A, et al. Odontogenic tumours, a collaborative retrospective study of 75 cases covering more than 25 years from Estonia. J Cranio-Maxillofacial Surgery 2004; 32:161-5

Response analysis and vibration control of suspension footbridges via tuned mass dampers

The dynamic response of suspension footbridges to pedestrian-induced excitations and its passive mitigation are investigated. The non-linear equations of motion are obtained and the finite-element code FEMLAB is used to solve both the eigenvalue and forced elastodynamic problems. Further, Ritz-Galërkin discretization approach is employed to solve the free and forced conditions for the design of the control system. First, the leading characteristics of the bridge dynamic response are outlined. Then, it is shown that resonant vibrations induced by the passage of pedestrians can be successfully reduced using visco-elastic tuned mass dampers (TMD), whose effectiveness has been proved to hold also with seismic excitations. The validity of the theoretically proposed method is confirmed in the case of an existing structure, the Singapore Suspension Footbridge

The retrieval of unerupted teeth in pedodontics: Two case reports

Introduction: The retrieval of unerupted teeth in pedodontics is always significant to preserve the trophism of adjacent tissues, establish the correct space, provide adequate function and maintain good esthetics for the patient. The treatment plan is based on radiographic examinations and measurements, and on an accurate clinical evaluation; it aims to achieve the best treatment possible depending on the complexity of the specific case. In the most difficult clinical cases it is very important to have an early diagnosis, which is essential to plan the treatment and achieve success. In these cases, the pediatrician is in a strategic position to give an early diagnosis through a child’s medical history and by counting the child’s teeth. Case presentation: This article presents two different difficult clinical cases of impacted teeth diagnosed during pediatric age, with a radiological analysis, and successfully treated with orthodontic devices designed for these specific cases. Clinical case 1 describes a 13-year-old Italian girl; clinical case 2 describes a 9-year-old Italian girl. The use of these devices achieved the desired treatment goals. The problems associated with impacted teeth and the biomechanical interventions used for these patients are discussed. Conclusions: An early and careful diagnosis followed by an accurate treatment plan for the individual cases can lead to retrieval of the impacted teeth without affecting other anatomic structures and adjacent teeth. In these cases, the pediatrician is in a strategic position to give an early diagnosis through a child’s medical history and by counting the child’s teeth

Three-part humeral head fractures treated with a definite construct of blocked threaded wires: finite element and parametric optimization analysis

Background: Mini open reduction and percutaneous fixation of three-part humeral head fracture with blocked threaded wires has demonstrated functional results similar to locking plates or intramedullary nails but with significantly lower major complication rate. In the context of three-part humeral head fractures, we performed a parametric optimization through a finite element analysis of a recently published construct to verify if the encouraging clinical results can be supported by a more rigorous investigation from a mechanical viewpoint. Materials and Methods: The 2-dimensional geometry of a three-part proximal humerus fracture synthetized with a system of blocked threaded wires was created. Tension/bending/shear and compression load tests were simulated. A parametric optimization analysis was performed considering four design parameters (height of wire couples; wire material; interdistance between two wires). Eighteen simulations were carried out. Additional analyses were performed also considering a varying diameter of the external rod. Results: Four points where the largest gap occurs and three points associated with the highest stress concentration were considered. As per the tension/bending/shear loading, a slight gap increase was observed in two different points (8.494 μm; 7.540 μm), while a slight decrease was detected along the greater tuberosity fracture line (1.445 μm). The maximum von Mises stress up to 64.4 MPa was achieved in the humeral head. As per the compression loading, the gap increased along the greater tuberosity fracture line (1.445 μm; 7.545μm); the maximum von Mises stress attains the value of 64.42 MPa. The smallest gap distance (15.37μm) and the lowest von Mises stress (51.51 MPa) were obtained in two different alternative constructs. The diameter of the external rod had no significant effect. Conclusions: The studied construct is biomechanically valid; it only allows micromovements (one-thousandth of the characteristic humerus size) that are not able to cause humeral head rotation and translation. Furthermore, the construct generates acceptable pressure stresses on sensible areas of the fractured humeral head. Compared to the original construct, we propose to space the pair of horizontal wires for the great tuberosity by at least 1 cm