RESUMEN
Twenty patients with complete dentures in both jaws gave up their maxillary ones for experimental purposes for 4 weeks while new dentures were made. The experimental dentures were reduced palatally to a new U-shaped border situated approximately 10 mm from the dental arch. Denture retention, defined as the ability of a denture to remain seated on the supporting tissues under various conditions, was measured as resistance towards cranially directed tilting loads, using a miniature bite force recorder. Dislodgement-provoking loads were applied to the first bicuspid on both sides and to the central incisors. The retention measurements were performed before and immediately after reduction of the palatal coverage and, finally, after 4 weeks. Interview questions were posed concerning the subjects' experience of denture retention and some other aspects of oral comfort. The interviews were carried out before reduction of the palatal coverage and after 2 and 4 weeks. The results of the experimental dislodgement tests suggested that the ability to withstand tilting loads was insignificantly altered by reduction of the palatal coverage. This finding was in agreement with responses indicating that retention during meals remained unchanged. However, several individuals reported that denture retention between meals was impaired. Three denture wearers reported that reduction of the palatal coverage influenced their sense of taste positively, and one reported that an occasional gagging tendency had disappeared. At the end of the experiment the participants were given the choice of a new conventional denture or a new denture without palatal coverage.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Retención de Dentadura , Dentadura Completa Superior , Hueso Paladar , Anciano , Comportamiento del Consumidor , Diseño de Dentadura , Dentadura Completa , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
The influence of complete maxillary denture design on retention was studied under clinical conditions simulating chewing. Five persons with an edentulous maxilla and a natural dentition of at least 10 teeth in the mandible participated. Retention was measured with a miniature bite force sensor. The occlusal load required to provoke denture dislodgement was recorded. The general principles of denture design were as follows: the bicuspids and molars were set on top of the residual ridge; the thickness of the denture borders was determined functionally; and the palate was covered to the vibration line, without attempts at border compressions. The details that were changed to evaluate their influence on denture retention were as follows: the point of attack of the dislodgement-provoking load alternated between three distinct pits, situated 2 mm apart in the buccopalatal direction on the occlusal surface of the first right bicuspid; the vestibular denture border on the left side was reduced stepwise to 75%, 50%, and 25% of its original thickness; and the distal extension of the palatal denture border was shortened stepwise (2 + 2 mm, as measured in the midline). Measurements pertaining to one specific problem were carried out within a period of 2 h. The results confirmed the concepts that lingualized occlusal contact, functionally determined filling in of the vestibular sulcus, and full palatal coverage to the vibration line all have a positive influence on the retention of complete maxillary dentures.
Asunto(s)
Diseño de Dentadura , Retención de Dentadura , Dentadura Completa Superior , Anciano , Fuerza de la Mordida , Femenino , Humanos , Masculino , Métodos , Persona de Mediana EdadRESUMEN
The influence of free tongue, lip, and cheek function on the retention of complete maxillary dentures was investigated for five experienced denture wearers. Test dentures were designed with full palatal coverage and functionally determined filling in of the vestibular sulcus. The front teeth were arranged primarily to meet cosmetic demands--that is, anterior to the top of the residual alveolar ridge. Retention was measured as resistance to dislodgement-provoking loads applied vertically to the incisive edge of the central incisors, using a miniature bite force recorder. All the participants were able to load their front teeth with 35 N or more without loss of retention. None of them experienced denture dislodgement provided the tongue, lips, and cheeks wee allowed to act freely. If the peripheral soft tissues were separated from the vestibular denture flange, no obvious effect on denture retention could be detected. Physically preventing the tongue from pressing against the posterior part of the denture reduced the retention significantly. Measurements of anterior loads tolerated after stepwise reductions of the denture extension indicated that the tongue acted primarily by pressure against the tuber regions. Tongue pressure against the central parts of the palate and lip or cheek pressure against the vestibular flange seemed to be of less importance.
Asunto(s)
Mejilla/fisiología , Retención de Dentadura , Dentadura Completa Superior , Labio/fisiología , Lengua/fisiología , Anciano , Fuerza de la Mordida , Análisis del Estrés Dental , Diseño de Dentadura , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Complete maxillary dentures were tested for their ability to remain in place when subjected to unilateral occlusal loads. The test material comprised five persons, each supplied with three identical dentures. The denture design was based on the principles of 1) functionally determined filling-in of the vestibular sulcus, 2) palatal coverage to the vibration line without post dam, 3) aesthetically governed positioning of the front teeth, and 4) positioning of the lateral teeth in the plane connecting the top of the residual ridge with the central part of the occlusal surface of the antagonizing natural teeth. Resistance to unilateral occlusal loads was measured by means of a miniature bite force sensor. In the pooled material, an average load of 70 N was tolerated before the dentures were dislodged. For a given participant/denture combination, the resistance against dislodgment varied considerably when tested on different days. Marked differences were also found among three identical dentures in one person. The tolerance against unilateral occlusal loads could feasibly be quantified. However, the influence of specific clinical and/or technological factors on denture retention during function should be studied only if strict definitions as to the test conditions are given. These conditions must include the time, person, and denture tested.