Nature of occlusion during eccentric mandibular movements in young adults.

AIM: The aim of this study was to find out the nature of occlusion and tooth contact during various eccentric mandibular movements in young adults with class I occlusion. MATERIALS AND METHODS: The sample consisted of 100 young adults with class I occlusion with full complement of teeth. Anterior disclusion in centric occlusion was demonstrated using a shim stock interposed between the upper and lower anteriors. Disclusion of posteriors was ascertained during 1.5 mm straight protusion and in edge-to-edge protrusion, visually as well as using a silk floss method. Posterior disclusion was also verified during lateroprotrusion and crossover. Besides these occlusal wear of teeth also were observed. RESULTS: The results of this study showed that the anterior disclusion is seen only in one-fourth of the subjects compared to almost three-fourth showing posterior disclusion. Mutually protected occlusion was also seen only in one-fourth of the subjects. Canine protective mechanism is seen in a relatively large number of subjects, but it was not overwhelmingly predominant. No correlation could be established between cuspid wear and the type of occlusion. A relatively high percentage of subjects showed wear on posterior teeth when there was no posterior disclusion. CONCLUSION: From the above study it is seen that posterior disclusion is acknowledged as a common factor except when a bilateral balance is present. Since bilateral balance is harmful, the ideal occlusal relationship in eccentric movements is in favor of posterior disclusion. Posterior disclusion is easily obtainable when restorations are planned. CLINICAL SIGNIFICANCE: From the findings and results it has been possible to make some contributions on the nature of tooth contacts and disclusion during various eccentric movements and compare it with the requirements of ideal occlusion.

An in vitro investigation into the cytotoxicity of methyl methacrylate monomer.

Aim of this study was to assess the cytotoxicity of monomer. An in vitro study was designed to study the growth inhibitory effect of monomer (Stellon, Denture Material Improved, Type I, Class I, Dental Products of India Limited) on cells seeded in petri dishes and maintained in an incubator with 5% carbon dioxide at 37 °C. The growth of V79 cells (fibroblast cells) maintained in a culture medium to which monomer was added was studied for a period of 5 days. Results of this study pointed out that even at a concentration of 1 µl of monomer, the cell growth was significantly inhibited, when compared to the control group. The number of viable cells decreased dramatically whereas dead cells increased in the culture groups treated with the monomer. The cytotoxic effect was dose dependent. As the concentration increased from 1 to 10 µl there was a marked inhibition of cell growth and a corresponding increase in dead cell count. Results of this study proved beyond doubt that monomer is indeed cytotoxic even in very low concentrations. Thus, it becomes imperative to adopt every possible means to minimize residual monomer content in heat cured resins. Also precautions to minimize tissue contact should be taken while handling monomer by the dentist and dental personnel in the laboratory.

Contemporary concepts in treatment planning, reconstruction and rehabilitation of the maxillofacial region: an overview of methods used in practice.

Treatment planning, reconstruction and rehabilitation of maxillofacial and dental defects have always been a challenge for a maxillofacial surgeon. Reconstruction of the oral cavity is often a difficult task as it involves the restoration of both the esthetic or cosmetic form as well as the preoperative function. Understanding the oral cavity anatomy as well the functional capacities of its various subunits is required to achieve good results. The recent advances in treatment planning, diagnostic imaging and reconstructive techniques, especially in the field of osseointegration, tissue expanders, perforator flaps, microvascular free tissue transfer and bone engineering, have yielded excellent functional and esthetic outcomes. This article provides a brief overview on various advanced reconstructive and rehabilitation techniques available in contemporary clinical practice.