RESUMO
Considering biomechanics of oral implants, both loading on the implant itself and the transferred load to the bone need our attention. Mastication induces vertical and transverse forces, which induce axial forces and bending moments and exert stress gradients in the implant as well as in the bone. By the use of strain gauges or piezo-electric force transducers, one succeeds in precise intra-oral force measurements which make it possible to study a wide range of varying conditions in implant dentistry. A key determinant of the success or failure of an oral implant is the way mechanical stresses are transferred to the surrounding bone. The load transfer from implants to surrounding bone depends on the type of loading, the bone-implant interface, the length and diameter of the implants, the implant shape, structure of the implant surface, the superstructure and the quality and quality of the surrounding bone. Finite element analyses indicate maximum stress concentrations in the contact area of the implants with the cortical bone and around the apex of the implants in the trabecular bone. Although the precise mechanisms are not fully understood, it is clear that there is an adaptive remodelling response of the surrounding bone to the current situation.
Assuntos
Implantação Dentária Endóssea , Fenômenos Biomecânicos , Humanos , Osseointegração/fisiologia , Desenho de Prótese , Falha de Prótese , Estresse MecânicoRESUMO
Preliminary investigations with telemetric urodynamic equipment permit us to describe the following indications for this technique: (1) repeated pressure/flow studies, both in obstruction and in experimental work; (2) when urge incontinence is expected on the grounds of the patient's history but standard cystometry reveals a stable bladder; (3) enuresis nocturna and psychogenic voiding dysfunctions; (4) in the therapy of incontinence. Some examples are presented.
Assuntos
Monitorização Fisiológica/instrumentação , Telemetria/instrumentação , Bexiga Urinária/fisiologia , Adulto , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pressão , Transdutores , Incontinência Urinária/fisiopatologia , UrodinâmicaRESUMO
Evoked urethral and anal responses are produced by electrical stimulation of penis, bladder neck and anus. Latency and duration of the responses after bladder neck and anal stimulation are greatly dependent on stimulus parameters, suggesting a polysynaptic reflex; penile stimulation probably involves an oligosynaptic pathway. In pathological conditions the responses are delayed and their duration reduced.