RESUMEN
An in vitro test is described that simulates the in vivo fate of a denture adhesive, namely destruction, dilution, and dissolution of the adhesive, by repeated measurement of tensile bond strength for the adhesive in isotonic saline over time. The bond strengths were measured under two different settings of the testing machine. The main compositions of three denture adhesive pastes, Fittydent, Fixodent, and Super Poli-Grip and one powder adhesive, Super Wernet's, were determined by infrared spectroscopy. The tensile bond strengths of these adhesives and those of pure tragacanth gum were subjected to a three-way analysis of variance. The Fittydent and Super Poli-Grip adhesives exhibited the best results over time. The most appropriate of the described methods for testing denture adhesives seem useful; however, when seen in relation to the results of a published clinical study where the patients were asked to evaluate the retention and the duration of some of these adhesives, there are indications that the clinical validity of the method might be improved if paste adhesives are tested at temperatures above 35 degrees C.
Asunto(s)
Adhesivos , Retención de Dentadura/métodos , Adhesivos/química , Análisis de Varianza , Carboximetilcelulosa de Sodio , Materiales Dentales , Análisis del Estrés Dental/instrumentación , Análisis del Estrés Dental/métodos , Humanos , Ensayo de Materiales/instrumentación , Ensayo de Materiales/métodos , Fosfatos , Polímeros , Polivinilos , Espectrofotometría Infrarroja , Resistencia a la Tracción , TragacantoRESUMEN
An in vitro test method is described simulating the in vivo fate of a denture adhesive, i.e., destruction of the adhesive, dilution, and dissolution, by measuring the bond strength for the adhesive placed between acrylic resin plates. Between each measurement, the adhesive was exposed to isotonic saline. The bond strength for two ointment denture adhesives, Super Corega and Fixodent, was measured and the results were compared with those obtained for one of them in a previous in vivo test. The test method described for denture adhesives seems useful to depict the fate of a denture adhesive in clinical use.
Asunto(s)
Adhesivos , Recubrimiento Dental Adhesivo/normas , Cementos Dentales , Materiales Dentales , Análisis del Estrés Dental/métodos , Retención de Dentadura , Análisis de Varianza , Fosfatos de Calcio , Humanos , Ensayo de Materiales/métodos , Fosfatos , Polímeros , Cloruro de SodioRESUMEN
The characteristics of the masseter reflex evoked by tapping a maxillary incisor were compared with the reflex pattern evoked by tapping a corresponding denture tooth after insertion of an immediate denture. Up to three inhibitory phases (I-1, I-2 and I-3), followed by excitation, were found on an averaged EMG. The tapping force threshold for the early inhibitory phase was lower than for the late phases. The pattern of the reflex was generally the same before and after insertion of the denture, but the threshold values increased. After insertion of the denture, the threshold for I-1 increased from 1 +/- 0.3N to 2.2 +/- 0.4N, the threshold for I-2 increased from 2.4 +/- 0.8N to 3.8 +/- 0.9N, and the threshold for I-3 increased from 5.1 +/- 0.6N to 8.3 +/- 0.9N. The latency period for I-1 also increased from 12.3 +/- 0.5 ms to 13.1 +/- 0.3 ms after insertion of the denture. After relining, the threshold for evoking I-1 decreased from 2.7 +/- 1.2N to 1.2 +/- 0.6N. It was assumed that the mechanoreceptors situated in the mucosa under the denture base could take over the functional role of the periodontal mechanoreceptors for evoking the masseter reflex during tapping, and that these afferents probably had connections to the same interneurones.
Asunto(s)
Dentadura Completa , Músculo Masetero/fisiología , Reflejo/fisiología , Diente/fisiología , Dentadura Completa Inmediata , Dentadura Completa Superior , Electromiografía , Potenciales Evocados/fisiología , Humanos , Incisivo , Percusión , Tiempo de Reacción , Factores de Tiempo , Extracción DentalRESUMEN
Denture retention may be defined as the ability of a denture to remain seated on the supporting tissues under various conditions. Soft tissue function influences the retention of removable prostheses by exerting pressure against the polished surfaces. The magnitude of this pressure on complete maxillary dentures under experimental conditions was studied. Five denture wearers participated. Miniature pressure transducers were placed at nine selected locations on the polished surfaces of the dentures: one on each tuberosity, three along the vibration line, and four on the vestibular flanges. The transducers were flush with the polished surfaces but discernible to the participants. Ultra-thin electrical wires connected the transducers to a power supply and recording equipment. Loading the incisors with 40 N in a cranial direction elicited soft-tissue pressure against the transducers. The highest values were recorded in the region of the tuberosities (51 kPa). Intermediary values were recorded along the vibration line (27 kPa), and the lowest pressure was recorded on the vestibular flanges (17 kPa).
Asunto(s)
Retención de Dentadura , Dentadura Completa Superior , Labio/fisiología , Lengua/fisiología , Anciano , Humanos , Persona de Mediana Edad , Hueso Paladar , Presión , TransductoresRESUMEN
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
In order to obtain a replica technique suitable for a complete or segments of a dental arch two different impression materials were combined with two epoxy resin model materials. The models were examined and photographed in an optical microscope and a scanning electron microscope. No systematic differences were found between the used combinations of materials except a tendency towards greater contraction of one of the model materials. The A-silicone impression materials combined with one of the epoxy resin material seemed to be the easiest to handle and to give the best models.
Asunto(s)
Materiales de Impresión Dental , Restauración Dental Permanente , Microscopía Electrónica de Rastreo/métodos , Diente/anatomía & histología , Sulfato de Calcio , Resinas Epoxi , Estudios de Evaluación como Asunto , Humanos , Masculino , Persona de Mediana Edad , Modelos Dentales , Proyectos Piloto , Elastómeros de Silicona , Propiedades de SuperficieRESUMEN
Maximal mouth opening, translatory condylar motion (radiographically assessed) and bite force in sixteen adults with rheumatoid arthritis and radiographic temporomandibular joint abnormalities were compared with data from sixteen individuals without joint disease. Mean mouth opening in the arthritis group was reduced, but not statistically significant. Condylar translation and bite force showed significantly lower values than in the healthy individuals. Maximal mouth opening seemed to be the most uncertain parameter for the estimation of jaw function. In seven patients with a normal mouth opening (40-46 mm), both the condylar translation and the bite force were significantly impaired.
Asunto(s)
Artritis Reumatoide/fisiopatología , Fuerza de la Mordida , Oclusión Dental , Trastornos de la Articulación Temporomandibular/fisiopatología , Adulto , Anciano , Artritis Reumatoide/diagnóstico por imagen , Femenino , Humanos , Masculino , Cóndilo Mandibular/diagnóstico por imagen , Cóndilo Mandibular/fisiopatología , Persona de Mediana Edad , Boca/fisiología , Movimiento , Radiografía , Trastornos de la Articulación Temporomandibular/diagnóstico por imagenRESUMEN
The maximal bite force was recorded between antagonizing anterior teeth in a group (n = 10) of patients with pathologic attrition and in a control group. No statistically significant difference between the maximal bite forces was recorded. Also, the effect on the maximal bite force of the continuous wearing of a partial bite raising splint for 4 months was recorded. The great individuality in reaction patterns prohibited simple generalizations. However, in some individuals the maximal bite force was larger when biting on the splint than without, both at base line and after 4 months. Also, the maximal bite force showed a tendency to increase with time. The findings indicate that pathologic attrition is not necessarily associated with a high maximal bite force. Also, the maximal bite force recorded under various conditions is seemingly not an absolute value but rather the result of a number of factors of varying importance for different individuals.
Asunto(s)
Fuerza de la Mordida , Oclusión Dental , Abrasión de los Dientes/fisiopatología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Férulas (Fijadores) , Abrasión de los Dientes/patologíaRESUMEN
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
Elastomeric impression materials for fixed prosthodontics are considered most stable when they have an even thickness of 2 to 4 mm. To obtain this, a custom-made impression tray is recommended. The purpose of the present study was to compare the stability of impressions made in custom trays and trays made of chromium-plated brass. The impression materials chosen were polyether and silicone. Two master models of the upper jaw were made of metal. The canines and first molars represented abutment teeth with flat occlusal surfaces. An engraved cross on each surface made it possible to measure in a microscope the distances between the abutment teeth on the models and in the impressions. The accuracy of the method was within +/- 8 micron. Twelve standardized impressions were made with each impression material in the two types of trays. The distances between the abutment teeth were measured immediately on removal of the impression, and after 1 and 24 hours. Although ample amount of impression material (2 to 9 mm) was allowed, the linear dimensional stability of the impressions made in stock trays was not inferior to the stability of impressions made in custom-made trays.
Asunto(s)
Materiales de Impresión Dental , Técnica de Impresión Dental/instrumentación , Goma , Resinas Acrílicas , Aleaciones , Resinas Sintéticas , Elastómeros de Silicona , Propiedades de SuperficieRESUMEN
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.
Asunto(s)
Oclusión Dental Balanceada , Retención de Dentadura , Dentadura Completa Superior , Anciano , Análisis del Estrés Dental , Diseño de Dentadura , Femenino , Humanos , Arcada Parcialmente Edéntula/fisiopatología , Arcada Parcialmente Edéntula/terapia , Masculino , Maxilar , Persona de Mediana EdadRESUMEN
There appears to be a relation between accumulation of plaque on complete maxillary dentures and denture stomatitis. The present index was introduced to assess the location and amount of plaque in some areas of the fitting surfaces of complete maxillary dentures. Scores were recorded in five defined areas on the denture base. Four ranked scores were used: 0 - no visible plaque, 1-plaque visible only by scraping on the denture base with a blunt instrument, 2-moderate accumulation of visible plaque, and 3-abundance of plaque. By summing up the scores from the five areas, the plaque was recorded on a scale from 0 to 15 points. The inter- and intra-reliability were tested for two examiners using the index on 50 complete maxillary dentures. Expressed in terms of Scott's Pi, inter-examiners agreement was 0.83, and intra-examiner 0.83 and 0.82 for examiners A and B, respectively. A simplification of the index was also presented. In this index the scores 0 and 1 were combined to score 0, -no visible plaque, and score 2 and 3 were combined to score 1, -visible plaque. Using this index, Scott's Pi was calculated to 0.91 for inter-examiner reliability. For the intra-examiners reliability Scott's Pi was calculated to 0.91 for examiner A and 0.89 for examiner B.
Asunto(s)
Encuestas de Salud Bucal , Índice de Placa Dental , Dentadura Completa Superior , Animales , Placa Dental/complicaciones , Humanos , Juicio , Persona de Mediana Edad , Estomatitis Subprotética/etiologíaRESUMEN
Solid state components were used to construct a miniature bite force recorder suitable for registrations in large study groups. A semiconductor was chosen as the sensory unit. The complete recording system included a power supply, the bite force recorder, a chart recorder and a millivoltmeter. Laboratory calibration tests were performed to screen the limitations of the recorder. Series of loads were applied in the range from 10 to 1000 N. Eight females and eight males, 20 to 25 years old, were asked to produce a succession of maximum bites at three second intervals for as long as possible. The bite force recorder was positioned between the first molars on the left side. The laboratory tests showed that loads in the range from 10 to 1000 N were recorded with an error less than four percent. In the clinical tests, the mean maximal bite force was 500 N ranging from 330 to 680 N. The number of maximum bites varied from 5 to 27. No statistically significant differences were observed between the sexes as regards the maximal bite force and the number of bites.
Asunto(s)
Oclusión Dental , Análisis del Estrés Dental/instrumentación , Transductores de Presión , Transductores , Adulto , Diseño de Equipo , Femenino , Humanos , Masculino , Músculos Masticadores/fisiología , Contracción Muscular , Estrés Mecánico , Factores de TiempoRESUMEN
Oral conditions were studied clinically and radiographically in a group of people aged 67-94 years. The group comprised 70 persons living in an institution for elderly people and 111 persons living in their homes in the surrounding area. The participants were classified according to sex, age and former occupation. The examination was carried out in a dental office established at the institution. 63% of the participants were dentulous with a mean number of 13 teeth. Almost 50% of the teeth were previously restored and 13% of the teeth were decayed at the examination. 45% had complete maxillary dentures and 39% had complete mandibular dentures. The need for dental treatment according to defined criteria was registered, and treatment-offers were given. Comparisons were made between the treatment suggested and the treatment actually given. Of the total group, 129 persons needed dental treatment. Of these, 65 persons accepted all or part of the treatment suggested. In general, sex was not a good predictor of the need for an acceptance of dental services. However, age was found to be useful as a predictor. Social background was an unreliable predictor of the need for and acceptance of dental services.