RESUMO
BACKGROUND: To evaluate the bone mineral density in the mandible of edentulous patients at prospective intraoral implant sites. Pre-operative evaluation of bone density is essential to assist the clinician with the treatment planning of implant supported prosthesis. MATERIALS AND METHODS: A study group of 12 edentulous subjects comprising of six male and six female between the age group of 45-55 years seeking implant supported prosthesis were selected. A radiographic stent using auto polymerizing resins incorporating the gutta-percha cones were prepared for the computed tomography scan. The bone mineral density values were recorded in various sites (trabecular and cortical) of the mandibular jaws in Hounsfield units. The data thus obtained were tabulated and statistically analyzed using Mann-Whitney U-test and Kruskal-Wallis test. RESULTS: The bone mineral density in the buccal cortical region of mandible increases from incisors to molars and in the trabecular region it is more in the incisors and canines compared to the premolar and molar regions whereas in the lingual cortical region of mandible may lie on nearly the same level over the entire lingual cortex. The bone mineral density is little higher in males than females. CONCLUSION: There is variation in the bone mineral density in the buccal cortex and trabecular bone, but no significant variation in the lingual cortex when compared between male and female subjects.
RESUMO
Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base.
