Functional And Esthetic Rehabilitation Of Severely Worn Dentition With Shortened Dental Arch Concept.

In the twenty-first century, patterns of dental disease in adults are changing. Surveys of adult dental health indicate that more people are keeping their teeth for longer in life. In many cases, the ravages of dental disease and the cumulative effect of a lifetime of restorative dentistry lead to gradual tooth loss. For many of these patients, restoration of a complete dentition may neither be feasible nor desirable. In recent years, functionally oriented treatment planning has become acceptable in light of recent research findings. Using this approach, treatment efforts and resources are directed principally at retaining the 'strategic' part of the dentition in the long term, ie, the anterior and premolar teeth.

Mechanical behavior of Ethylene Vinyl Acetate copolymer (EVA) used for fabrication of mouthguards and interocclusal splints

In the present investigation, an experimental dental arch model fabricated in epoxy was assayed in Kratos universal testing machine to study the mechanical behavior of ethylene and vinyl acetate copolymer (EVA) in the form of mouthguard for sports and flat plate. The following variables were considered: thickness (3 and 4-mm plates), temperature (room and mouth temperature) and presence/absence of artificial saliva. Mechanical properties of EVA were tested under compressive strength: apparent absorbed energy (J.mm-1), maximum tension (N.mm-1), maximum dislocation (mm) and maximum strength (N). Data were recorded and modeled mathematically. Regarding the absorbed energy, maximum tension and maximum force, it was verified that the higher the thickness of the mouthguards, the better the results of force dissipation and redirection to the system and to several regions of the dental arch. In the presence of saliva and close to mouth temperature, the material responded positively to these alterations, resenting increased ductibility as well as improved mechanical responses. Regarding maximum dislocation, it was observed a better accommodation of the occlusion under conditions that simulate those observed in the oral environment. In conclusion, EVA proved to be an adequate material for fabrication of mouthguards and interocclusal splints. In addition, EVA showed good results in force dissipation and demonstrated a shock-absorbing capacity and a great protection potential.

Um modelo experimental de arco dentário, obtido em epóxi, acoplado a uma máquina universal de ensaios Kratos, foi utilizado para estudar o comportamento mecânico do copolímero de etileno e acetato de vinila (EVA), na forma de protetor bucal para esporte e placa plana. As seguintes variáveis foram observadas: espessura (lâminas de 3 e 4 mm), temperatura (ambiente e bucal) e presença ou ausência de saliva artificial. As propriedades mecânicas do EVA, foram testadas ao esforço compressivo: energia aparente absorvida (J.mm-1), tensão máxima (N.mm-1), deslocamento máximo (mm) e força máxima (N). Dados foram registrados e modelados matematicamente. Considerando a energia aparente absorvida, tensão máxima e força máxima, verificou-se que com o aumento da espessura dos protetores bucais houve melhores resultados de dissipação de forças compressivas e seu redirecionamento para o sistema e diversas regiões do arco dental. Com a presença de saliva e temperatura próxima a bucal o material respondeu positivamente a essas alterações aumentando sua ductibilidade apresentando assim melhora em sua resposta mecânica. Com respeito ao deslocamento máximo observou-se que houve melhor acomodação da oclusão quando em condições próximas à bucal. Conclue-se que o EVA provou ser um material adequado para a confecção de protetores bucais para esporte e placas interoclusais.O EVA mostrou melhores resultados na dissipação de forças demonstrando sua grande capacidade amortecedora e grande potencial de proteção.

Appliance of Interocclusal Splint as Initial Treatment of TMJ Dysfunction

TMJ dysfunction has difficulties for diagnosing and treating, and its symptoms are variable. TMJ dysfunction is classified as muscular problem, capsular problem, ligamentous problem, internal derangement, or condylar dislocation etc. Treatment modalities for TMJ dysfunction are surgical or conservative one, but they haven't be standardized. Because of anatomical complexities and difficulties of surgical approaches, conservative treatment have been preferred. We've had 30 cases having impressed capsular tightness or internal derangement. They have made an appeal for pain on TMJ area, ROM limitation of joint, clicking etc. We have used the interocclusal splint as treatment modality. In general, the interocclusal splint is classified as the stabilization splint, the repositioning splint, the pivot splint, the soft splint etc. We have applied the stabilization splint or the repositioning splint to the patients according to diagnosis or symptoms. The interocclusal splint is reported to induced the changing activities of muscle, altering the stress or loading of the joint and recapturing or changing condyle- disc-fossa position. As a result, the pain has become reduced and ROM limitation of joint was improved, clicking is eliminated initially. From January 2001 to May 2002, we treated 30 patients who having TMJ dysfunction. Our treatment modality was performed that the interocclusal splints were worn full time for one to four weeks, then phased out. During the mean 10.5 months of follow-up period there had been significant improvements in pain, ROM limitation of joint and clicking. After 6 months, there had been no recurrence in pain and ROM limitation of joint, but 2 cases recurred in clicking that has disappeared. The appliance of interocclusal splint has been an effective method for the initial nonsurgical treatment of the symptoms of TMJ dysfunction. However, more in-depth study by long term follow-up is needed to evaluate recurrence.