Mandibular guidance prostheses following resection procedures: three case reports.

Unilateral loss of mandibular continuity creates problems in prosthetic reconstruction. For dentate patients, palatal guide ramps or mandibular guide flange prostheses are indicated. Edentulous patients are much more difficult to retrain in mandibular movements, but complete dentures designed with stabilising occlusal contacts can be successful in compensating for the deviation. Three case reports are presented.

Evaluation of impression tray techniques in microstomic patients.

Three different methods of constructing impression trays for patients suffering from microstomia have been described. When sectional trays with connectors are designed, proper alignment of the sections is necessary for satisfactory results. Flexible trays, or even silicone putty without a tray, can be used for making preliminary impressions in these cases.

Adsorption of human salivary mucin MG1 onto glow-discharge plasma treated acrylic resin surfaces.

It has been suggested that altering the surface properties of acrylic resin material may change the nature of the adsorbed pellicle affecting denture retention and microbial adherence. This study aimed at evaluating the adsorption of salivary high molecular-weight mucins, a major component of denture pellicle, onto modified acrylic resin surfaces. (Poly) methylmethacrylate specimens were treated by glow discharge plasma technique, using hydrophilic 2-Hydroxyethylmethacrylate monomer or oxygen (O(2)) gas and hydrophobic Hexamethyldisiloxane monomer, at different discharge powers. Acrylic samples were incubated with high-molecular weight mucin, MG1 purified from saliva, the adsorbed fractions were transferred to nitrocellulose membranes by slot-blot technique, stained by periodic acid-Schiff and colour intensities were analysed by a colour densitometer. Higher amounts of mucins were adsorbed on all the surfaces modified by glow-discharge plasma treatment. Within the limitations of this study, it was concluded that glow-discharge plasma altered the surfaces of acrylic resin denture base materials and significantly increased the adsorption of high molecular-weight mucins at varying levels depending on plasma parameters.

Adherence of Candida albicans to glow-discharge modified acrylic denture base polymers.

An important aetiologic factor in the pathogenesis of denture-induced stomatitis, is the presence of numerous yeasts, usually Candida albicans, on the fitting surfaces of dentures. In the present study, effect of glow-discharge plasma, a technique applied to increase surface wettability of acrylic resins, on candidial adherence was evaluated. The durability of glow-discharge modification with saliva coating was also evaluated. Samples including control and experimental groups were prepared by using heat compression mould technique. To create a hydrophobicity gradient, experimental groups were exposed to a radiofrequency glow discharge in an O2 atmosphere under different discharge powers. To characterize the wetting properties, an expression of surface hydrophobicity, contact angle measurements were performed by the sessile drop method. The organism used was C. albicans (ATTC10321). Acrylic samples were coated with unstimulated whole saliva collected from a healthy man. The fungal suspension was poured on saliva-inoculated samples and incubated at 37 degrees for 2 h. The samples were then fixed with glutaraldehyde and Gram stained. Adhered candidial cells were examined by light microscope. Diffuse Reflectance FTIR (DRIFT) and scanning electron-microscope examinations were also performed to evaluate the surface composition and roughness of the test groups. Glow-discharge plasma was found to be an effective means of increasing surface wettability even with salivary pellicle. Amounts of candida cells adhered were significantly higher in all the plasma treated surfaces than the unmodified control group (P < 0.001). It was concluded that improving the surface wettability of acrylic resins by glow-discharge plasma in O2 atmosphere increased the adherence of the C. albicans.

[Clinical comparison of different types of obturators constructed after maxillary resections]. / Ust çene rezeksiyonlarindan sonra uygulanan degisik tip obtüratörlerin klinik olarak karsilastirilmasi.

This investigation was carried on eight patients who had undergone partial maxillary resection for the eradication of tumors. Two types of obturators, one being hollow-bulb and the other buccal flange were constructed for each patient, using different impression techniques. When these were compared clinically, it was concluded that buccal flange obturators which were constructed without closed hollow sections were superior to the hollow-bulb obturators with closed nasal sections extending as far as possible into the anterior and lateral aspects of the defect, in comfort, function, speech and stabilization.

Evaluation of the level of residual monomer in acrylic denture base materials having different polymerization properties.

The aim of this study was to evaluate the level of residual monomer in acrylic denture base materials having different polymerization properties. The investigation included a conventional-type acrylic cured under heat and pressure, as well as a pour-type resin polymerized by an injection-moulding technique at room temperature and under pressure. It was found that the residual monomer content ranged from 0.22-0.54% in pour-type resin, and from 0.23-0.52% in routinely used resins when the specimens were analysed by high performance liquid chromatography. These findings revealed that there were no significant differences between the two types of acrylic in terms of their residual monomer content.

Cephalometric evaluation of maxillary complete, mandibular fixed-removable partial prosthesis: a 5-year longitudinal study.

Lateral cephalometric films were obtained from 10 subjects treated with maxillary complete dentures opposed to bar-supported mandibular removable partial dentures. The amount of bone resorption was determined following a 5-year period of denture use. In the maxilla, slight resorption was observed; a considerable amount had taken place in the mandible. Comparing the results of previous studies with the present one, it is suggested that bar-supported mandibular free-end saddle partial denture design has beneficial effects in terms of reduced bone resorption.

[Evaluation of the occlusal plane in dentulous and edentulous subjects]. / Disli ve dissiz vak'alarda okluzal planin sefalometrik olarak karsilastirmali degerlendirilmesi.

The occlusal plane is an important factor in stability and esthetic of dentures. The location of the occlusal plane in complete dentures is a controversial subject. The occlusal plane in complete denture has often been oriented anteriorly to fulfill esthetic and posteriorly to Camper's line. However, recently the methods used for locating the occlusal plane appear to be less limiting. The purpose of this investigation was to compare the different concepts of occlusal plane. A roentgenographic cephalometric investigation was conducted to compare the position of the occlusal plane of the artifical teeth with that of the natural teeth which existed before the remaining teeth were extracted.

[Electromyographic evaluation of different types of obturators constructed after maxillary resections]. / Ust çene rezeksiyonlarindan sonra uygulanan degisik tip obtüratörlerde kas fonksiyonlarinin elektromyografik olarak karsilastirilmasi.

Our investigation included 6 patients who had undergone extensive surgery for eradication of neoplasms of the maxillae. Their surgical defects were similar and they had natural teeth on the unresected side. Two types of obturators were constructed for each patient, one being hollow-bulb and the other buccal flange. The hollow-bulb obturators had closed nasal sections extending as far superiorly as possible into the anterior and lateral aspects of the defect. Buccal flange obturators were constructed without closed hollow sections. Our study was designed to compare these obturators electromyographically. When the results were evaluated statistically, it was concluded that buccal flange obturators were superior to hollow-bulb obturators in stabilization and function.

[Speech intelligibility in various types of obturators constructed after maxillary resections]. / Ust çene rezeksiyonlarindan sonra uygulanan degisik tip obtüratörlerin fonetik olarak karsilastirilmasi.

Six patients who had undergone partial maxillary resection for the removal of oral neoplasms were studied. For each patient two types of obturators were made one being buccal flange and the other hollow-bulb. Speech evaluations were made under three conditions: 1- with the hollow-bulb 2- with the buccal flange and 3- with no obturator. Speech evaluations were made both audiovisually and from tape recordings. In both audiovisual and tape recorded speech evaluations, the buccal flange obturator produced speech which was significantly superior to speech with hollow-bulb obturator.

The attenuation of radiation by porcelain and its effect on polymerization of resin cements.

The influence of porcelain thickness and opacity on the polymerization of two dual activated (microfine and hybrid) and one light irradiated (hybrid) resin cements was assessed by hardness measurements. The surface microhardness values of the upper and lower surface of 1 mm thick resin cement specimens were determined. Specimens were polymerized using 40s irradiation beneath different thicknesses and opacities of porcelain discs. The results showed that increasing the thicknesses and opacity of the porcelain produced a statistically significant decrease in microhardness of the resin-based cements. The effect of attenuation is less for the microfine cement than for the hybrids. In the case of hybrid cements, the light activated material performed better than the dual activated cement.

Microleakage of direct and indirect inlay/onlay systems.

The purpose of this in vitro study was to evaluate the microleakage of direct and indirect inlay/onlay systems. Two of the groups investigated have indirect applications only and consist of microfine composites. The other two groups of inlay/onlay systems have both direct and indirect applications and are hybrid composites. Standardized MOD preparations were cut in 60 extracted human premolars. One gingival margin was placed in enamel above the cementoenamel junction (CEJ) and the other was placed in dentine below the CEJ. The inlays were made and luted according to each manufacturer's recommendation. The restored teeth were thermocycled and immersed in a basic fuchsin solution for 24 h. Following the mesiodistal sectioning of the specimens, extent of dye penetration at the restoration-glass ionomer cement and tooth-glass ionomer cement interfaces were scored using a stereomicroscope. Both direct and indirect inlays showed substantial leakage at gingival-dentine margins. However, there was only superficial leakage at enamel margins. Comparing the overall indirect inlay systems, EOS inlay leaked the most (P < 0.05). Indirect Brilliant Dentin inlays showed a significantly smaller amount of leakage than the other inlay systems. SR-Isosit and Estilux Posterior C VS inlays provided a favourable marginal seal. In the case of Brilliant Dentin and Estilux Posterior C VS, indirect inlays leaked more than direct inlays. Generally, no significant difference was observed between the interfaces evaluated in microleakage performance.

[Overlay dentures]. / Overlay protezler.

Overlay dentures which are accepted as superposition appliances have been presented by three cases in this article. These kind of dentures are dedicated as prosthodontic restorations which are applied to extend maxillary arch horizontally in the cases of maxillary collapse. These restorations also increase the vertical dimension which has been lost and so help to improve the facial contour as well as esthetics of the individual-these dentures classified as removable partial or complete overlay dentures are generally applied in the cases of bilateral or unilateral maxillary collapse which have been caused by trauma or tumor resection.

[Evaluation of stresses in different cingulum rest seats]. / Farkli singulum rest yuvalarinin kuvvet iletimi yönünden karsilastirilmalari.

Both lingual and incisal rest seats are used on anterior teeth. Lingual rest seats are preferred since they are more acceptable esthetically and located closer to the centre of rotation of the tooth. Lingual rest seats can be prepared directly on the abutment teeth as grooves, shoulders or may require restorations such as crowns, inlays and prefabricated rest seats to provide proper contour. In this study, the stress induced by two conventionally applied rest seats were compared with that of the U shaped rest seats which were recently induced. As a result it is found that more uniform stress distribution occurred in U and inverted "v" type rest seat designs.