PubMed Health⌕ Search

Biomedical subjects

R Pilo

Publications and source records attributed to R Pilo.

16 recordsLinked to original sources
PubMed1992

The cantilever fixed partial denture--a literature review.

The cantilever fixed partial denture (FPD) is a restoration with one or more abutments at one end and unsupported at the other end. Forces transmitted through the cantilevered pontics can cause tilting and rotational movements of the abutments. In a cross-arch unilateral cantilever FPD, the distal cantilevered unit is subjected to comparatively less force than the contralateral posterior abutment. The unilateral lack of terminal abutments causes lateral bending forces activate peripheral inhibitory feedback reactions from the periodontal and/or temporomandibular mechanoreceptors. The greatest strain in distal cantilevered FPDs is recorded mesial to the most distal retainer because most fractures occur in this location. To improve the prognosis of the FPD cantilever, the number of abutments should be increased and the number of pontics decreased. The abutment teeth need long roots and acceptable alveolar support. Prepared abutments require adequate length and parallel axial walls. An equilibrated and harmonious occlusion is necessary, as well as exemplary oral hygiene. A cantilevered FPD with adequate periodontal support can replace any tooth in the dental arch, but is especially useful as an alternative to a removable partial denture. The cantilevered FPD requires at least two abutment teeth. The only documented exception permitting a single abutment is the replacement of a maxillary lateral incisor with the canine as an abutment. An alternative to the cantilevered FPD is the osseointegrated implant. As osseointegrated implants become more popular, the need for the tooth-supported cantilevered FPD may decline, but it will remain an alternative treatment modality.

Biomechanical Phenomena↗
PubMed1992

Post-irradiation polymerization of different anterior and posterior visible light-activated resin composites.

The Knoop hardness number was measured for bottom and top surfaces of 2 mm thick specimens of different anterior and posterior visible light-cured composites. The variables for this study included various exposure times and a series of time intervals from immediately after curing up to 72 h. Post-irradiation microhardness at the bottom and top surfaces increased rapidly over the first hour, was slower during 24 h and showed no further increase after 24 h. Increasing exposure time resulted in higher microhardness values at both surfaces. Magnitudes of change were larger for the bottom surface. Exposure times longer than those recommended by the manufacturers were needed, especially for the anterior microfilled composites, to achieve adequately photo-activated resin that had an optimum bottom/top surface microhardness of 80-90%. Maximum hardness values were found to be dependent on the volumetric fraction but not on the average inorganic filler size. The post-irradiation increase in hardness value was independent of composite parameters and is probably commensurate with polymerization kinetics.

Analysis of Variance↗
PubMed1991

Restoring teeth following crown lengthening procedures.

Crown lengthening procedures are often necessary to successfully restore teeth that have been mutilated at or below the level of the bone crest. Forced eruption is preferred to surgical removal of supporting alveolar bone, since forced eruption preserves the biologic width, maintains esthetics, and at the same time exposes sound tooth structure for the placement of restorative margins. To properly construct a crown, the minimal distance from the alveolar crest to the coronal extent of sound tooth structure should be 4 mm. Before initiation of forced eruption, the restorability of the root after completion of the orthodontic phase must be considered. A technique is suggested to calculate the root-to-crown ratio that will be created after root extrusion with respect to the coronal level of sound tooth structure before treatment.

Dental Restoration, Permanent↗
PubMed1990

Cuspal flexure associated with amalgam restorations.

Cavity preparation causes cuspal flexure under simulated occlusal loads. During amalgam condensation, the dentist exerts forces on the tooth. After condensation, dental amalgam undergoes dimensional changes. We measured possible changes in the cuspal position of premolars during and after their restoration with dental amalgam. Strain gauges were attached to the buccal surfaces of the teeth, and a direct reading of the strain and a simultaneous time-strain curve were obtained. Measurements were taken at the onset of amalgam condensation and continued for 24 hours. The amalgam was then removed from the teeth, and a subsequent reading was made. On the basis of this model, we found that the use of amalgam as a restorative material caused a static load on the cusps of the teeth brought about their consequent permanent deformation. After amalgam removal, we observed complete elastic recovery for all the treated teeth.

Biomechanical Phenomena↗
PubMed1990

A controlled putty-wash impression technique.

A precise impression is imperative for the construction of an accurately fitting indirect cast restoration. The putty-wash technique is commonly used in making impressions with silicone elastomers. Errors in manipulation may lead to inaccurate impressions. A technique is presented ensuring exact reseating of the putty impression tray and creation of a uniform wash space, which are essential for accurate results.

Dental Impression Technique↗
PubMed1989

Diagnostic casts--an additional dimension.

The indications and usefulness of diagnostic casts are well documented in the literature. A method is presented that enables increased access to the lingual aspect of the casts by sectioning them in a midsagittal plane. The sectioned portions are held together in maximum intercuspation by acrylic keys. The interdigitated casts can thus be examined from all aspects, thereby deriving maximum benefit from them.

Acrylic Resins↗
PubMedDate not supplied

Severe infraclusion ankylosis: report of three cases.

Tooth ankylosis may occur at any time during eruption and may show varying degrees of infraclusion. Cases of fully erupted teeth subsequently becoming totally embedded in bone are rare. The three reports described here show cases of severe infraclusion ankylosis; the etiology and related problems are discussed. Associated periodontal, prosthetic and orthodontic problems can be avoided with early diagnosis and treatment.

Adult↗