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At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

A 5,500 year old artificial human tooth from Egypt: a historical note.

Archaeological excavations at a Neolithic cemetery near Gebel Ramlah, Egypt yielded, among other finds, a life-size shell carving of a human tooth. Based on its spatulate crown and large conical root, the tooth most closely emulates a maxillary incisor. The crown's lingual and labial surfaces are suggestive of a left central incisor, whereas the occlusal view is more reminiscent of a left lateral incisor. The present report details the tooth's appearance and provides several interpretations concerning its function, including the possibility that it was intended to be a dental implant.

Dental Implants↗
PubMedDate not supplied

Development of a two-piece artificial resin tooth specially designed for a metal occlusal surface.

The traditional denture fabrication technique using resin teeth with metal occlusal surfaces is rather complicated and time consuming. To improve this, a new two-piece artificial resin tooth has been developed. The teeth are arranged on the wax denture and processed in the usual manner. The patient is allowed to use the completed denture for a period of time to harmonize the occlusal surfaces with oral function. The occlusal portions of the teeth are then separated from the base and invested as a resin pattern for casting. The new cast occlusal portions are reset on the base portions with a resin adhesive.

Denture Design↗
PubMed2001

An assessment of the ability of dental undergraduates to choose artificial teeth which are appropriate for the age and sex of the denture wearer: a pilot study.

One of the main objectives in selecting and arranging artificial teeth is to produce prostheses which defy detection. With an appropriate degree of clinical experience and expertise it should be a relatively straightforward procedure to select a suitable artificial tooth mould. However, for the relatively inexperienced dental undergraduate it can be a challenging process. The aim of this study was to assess the ability of dental undergraduates to select artificial teeth which are appropriate for the age and sex of the denture wearer. One hundred and fifty dental undergraduates aged 18-35 were asked to complete a questionnaire to assess their attitudes towards artificial tooth selection and asked to correctly identify six artificial tooth arrangements according to age and sex. The results showed that a large percentage of dental undergraduates at Bristol experience difficulty in selecting artificial teeth which are appropriate for the age and sex of the denture wearer. There is a need for improved training and guidance on artificial tooth selection and arrangement.

Adolescent↗
PubMedDate not supplied

Methods used to select artificial anterior teeth for the edentulous patient: a historical overview.

PURPOSE: Selecting artificial teeth for a denture is complex when there are no remaining natural teeth and no pre-extraction records. The aim of this paper is to review the methods used to select artificial anterior teeth for the endentulous individual. MATERIALS AND METHODS: The review takes account of the majority of papers published during the last 100 years and is organized according to the methods used for determining artificial tooth form. RESULTS: Several factors have been proposed as aids for artificial tooth selection, and numerous methods have been devised for the evaluation of reliable esthetic factors in determining artificial tooth form. CONCLUSION: To date, no universally reliable method of determining tooth form has been found. The Williams classification (1914) is the most universally accepted method of determining anterior tooth form.

Denture Design↗
PubMed2001

Development of an orthodontic simulator for measurement of orthodontic forces.

In this research we developed an orthodontic simulator for analysis of orthodontic forces distribution in the case of the continuous arch technique. In order to take into account vertical force, besides horizontal force and occlusogingival moment on instrumented artificial tooth, tooth root was designed as a ring load cell. Fixing each artificial tooth onto combined mechanical stages enabled variation of tooth anteroposterior position and inclination related to occlusal plane. Calibration of forces and moment of each instrumented artificial tooth showed linearity of outputs and provided the generalized inverse matrix for evaluation of forces and moments from measured strain data. A simulation to retract the anterior teeth was accomplished, and distribution of forces and moment acting at the bracket of each tooth were determined. The average accuracy was 82% and 97% in the horizontal and vertical direction, respectively, by comparing the applied forces and the evaluated ones.

Algorithms↗
PubMed1978

Arrangement of anatomic-type artificial teeth into balanced occlusion.

The mechanical factors which are involved in the arrangement of anatomic type artificial teeth into balanced occlusion have been described. Many of the mechanical problems encountered during artificial tooth arrangement have been listed, together with suggestions for their solution. Hanau's Laws of Articulation have been utilized in a practical manner in formulating some of the solutions to tooth arrangement problems when establishing balanced occlusion. Trial dentures which present ideal occlusions in the articulator may not always do so when examined in the patient's mouth. Possible reasons for these differences are listed, and methods for making the necessary corrections are described.

Dental Articulators↗
PubMed1997

Application of a three-dimensional reconstruction method to analysis of the residual ridge.

The purpose of this study was to develop a new method of analysing the shape of the residual ridge. The line of the residual ridge crest was regarded as the reference for artificial tooth arrangement and a method of determining it was evaluated. The shape of a plaster model was measured with a contact-type shape measurement system. The measurement data in each frontal section were interpolated by cubic splines. The points corresponding to the residual ridge crest were calculated and superimposed onto the image of the plaster model on a monitor screen of an image processor. Using these points and the image of the plaster model, the line of the residual ridge crest was marked on the plaster model. It was concluded that this method could be used to determine the line of the residual ridge crest on a plaster model.

Algorithms↗
PubMed1990

[The regulation of re-selection form in the aesthetic factor of upper anterior artificial teeth].

Sixty one cases of selection error due to the esthetic factors of artificial tooth forms were investigated out of the 72 cases of selection error which were committed at the department of Prodosthontics in Nihon University school of dentistry at Matsudo for 17 years from 1971 to 1988. The following were the results of investigation, 1. The cases of S-type were changed to those of ST-type, which emphasized the Tapering type factors. 2. The those of ST-type were changed to those of SO-type and S-type which emphasized the Ovoid type factors and got rid of the Tapering type factors. 3. The those of SO-type were changed to those of STO-type which emphasized the Tapering type factors. 4. The those of T-type were changed to those of TO-type which emphasized the Ovoid type factors. 5. The those of O-type were changed to those of TO-type and STO-type which emphasized the Tapering and Square type factors. The regulations of re-selection showed the tendency of changing from single form to complex form, emphasizing the Tapering type factors.

Denture Design↗
PubMed1998

Computer-generated study of the correlation between tooth, face, arch forms, and palatal contour.

STATEMENT OF PROBLEM: Several factors have been suggested as aids for artificial tooth selection. Numerous methods have been devised for the evaluation of reliable esthetic factors in determining artificial tooth form. There is no universally accepted single esthetic factor that can be used reliably to aid artificial tooth selection. PURPOSE: This article describes a new method incorporating a computer program to analyze four esthetic factors: form of the face, arch form, palatal contour, tooth shape, and to determine whether there was correlation between tooth, face, and arch forms and palatal contour. MATERIAL AND METHOD: Impressions were made of the maxillary dentition of 50 dentate undergraduate dental students with irreversible hydrocolloid impression material and casts formed. A standardized photographic procedure was used to record portrait slides of each subject's face and of maxillary dental arches and central incisors made from dental casts. A comprehensive computer program was developed to correlate esthetic factors by superimposition. RESULTS: Superimposing outline form between face, tooth, and arch showed that for tooth to face form nearly half the comparisons were dissimilar and only 22% corresponded. This is the lowest level of correspondence in this group. Highest correspondence (28%) occurred between arch to face form, followed by arch to tooth form (24%). Arch to tooth showed the lowest level of dissimilarity (32%). For correlation among the four factors across the sample group based on a comparison of classifications in each subject, men tended to dominate tapering classes, whereas women dominated square and ovoid classes. CONCLUSION: Correspondence of outline forms through superimposition revealed an insignificant correlation between face, tooth, and arch forms. Although this method applies high technology, it does not improve the accuracy of determining shape and size of teeth in an edentulous patient. The cost and complexity of the method of measurement may also make it impractical for common application.

Adult↗
PubMed1998

The influence of stress on edentulous maxillary bone with different artificial anterior tooth arrangements by three-dimensional photoelasticity.

OBJECTIVE: To investigate the influence of stress on edentulous maxillary bone different artificial anterior tooth arrangements, with the goal to establish theoretical evidence for optimal anterior tooth arrangements in complete denture restoration. MATERIALS AND METHODS: Three-dimensional photoelasticity experimental stress analysis was conducted. Shear stresses were measured and principal stresses were separated into six different models of maxillary central incisor arrangements. RESULTS: The value of maximum stresses and the absolute values of principal stresses and positive stresses were obtained. The distribution curve of shear stresses and principal stresses was also shown. CONCLUSIONS: The horizontal distance between the incisive papilla center and the incisal margin of the maxillary central incisor should be no more than 8 mm, if the anterior mandibular arch is larger than the maxillary arch. The principal stress is a better indicator of stress on edentulous maxillary bone when load is applied at the protrusive occlusal position.

Alveolar Process↗
PubMed1983

Interaction of human plasma fibronectin with cariogenic and non-cariogenic oral streptococci.

The interaction of purified human plasma fibronectin (Fn) with bacteria was studied with a variety of oral streptococci. Each of the strains of Streptococcus mutans, Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mitis tested was aggregated by Fn to various degrees, depending on the concentration of Fn added to the test mixtures. Binding assays performed with radiolabeled Fn and various strains of streptococci demonstrated various capabilities to bind Fn, and the amount of Fn bound by each strain was paralleled by its Fn-induced aggregation, with S. mutans 6715 giving the highest values in both assays. Because of the avid binding of Fn by certain strains of potentially cariogenic streptococci, we investigated the possibility that Fn may be present in human saliva and may be adsorbed from saliva onto artificial tooth pellicles. Immunoreactive Fn was detected in paraffin-stimulated whole saliva by enzyme-linked immunosorbent assays of saliva adsorbed onto gelatin-coated cuvettes and by immunoelectroblots (Western blots) of salivary components separated on sodium dodecyl sulfate-polyacrylamide slab gels. Furthermore, immunoreactive Fn was found to be present in artificial tooth pellicles formed by incubating hydroxyapatite beads with whole human saliva. These results demonstrate that certain strains of oral streptococci bind to and are aggregated by Fn. The presence of Fn in artificial tooth pellicles suggests that this macromolecule may play a role in the attachment of potentially cariogenic and other oral streptococci to dental tissues.

Fibronectins↗
PubMed1979

Porous titanium endosseous dental implants in Rhesus monkeys: microradiography and histological evaluation.

Artificial tooth roots with porous surface coatings were fabricated by sintering spherical powder of titanium alloy to solid cylindrical cores. The tooth roots were implanted subgingivally in healed mandibular premolar extraction sites of fifteen Rhesus monkeys. Supracrestal abutments were screwed into pretapped holes in the superior aspect of the primary subgingival stage four to eight weeks after implantation of the root. Clinical evaluations were performed monthly. Ten animals were sacrificed for histological evaluation of the functioning free standing implants. Of twenty-nine implants placed, three were lost and four were rated failures on the basis of histological evaluation. Postmortem evaluations revealed bone growth into the porous surface coating of the primary stage of all the implants. The most characteristic features which could be used to describe differences in the implant histology were the buccal and lingual crestal bone heights measured in relation to the root porosity. Twelve of sixteen implants had crestal bone heights within one millimeter of the superior aspect of the root. Four other implants displayed excessive bone recession, revealing as much as one half of the root porosity supracrestally. The four implant failures could be related to unfavorable features of recipient bone sites. The results demonstrate that the bone growth into the porous surface coatings of artificial tooth roots is an efficacious method of dental implant fixation.

Alloys↗
PubMed1986

Interaction of salivary fibronectin with oral streptococci.

Immunoreactive Fibronectin (Fn) has been demonstrated in stimulated human parotid saliva by western blot analysis and also found to be a component of the artificial tooth pellicles derived from hydroxyapatite (HA) beads coated with parotid saliva. Saliva depleted of gelatin-binding components showed a significantly lower degree of reactivity with anti-Fn antibodies than did the control saliva when tested by and enzyme-linked immunosorbent assay (ELISA). Depletion of gelatin-binding components from saliva was also found to affect the degree of saliva-mediated aggregation of four of the seven oral streptococci tested [Streptococcus mutans strains GS-5 and OMZ 176, S. sobrinus, and S. rattus]. Similarly, the adherence of the same four micro-organisms to the artificial tooth pellicles (derived form saliva which had previously been depleted of gelatin-binding component) was significantly inhibited (37-53%) when compared with the control saliva-coated HA beads. Pre-treatment of streptococci with 100 micrograms of soluble Fn also caused a 34-57% inhibition of adherence of the same oral streptococci to saliva-treated HA beads. Quantitation of Fn in human parotid saliva showed that the amounts of immunoreactive Fn varied form 2 to 6 micrograms/mL of parotid saliva. Furthermore, the Fn from parotid saliva was found to be adsorbed onto the bacterial surfaces, as demonstrated by immunofluorescence and ELISA. The presence of Fn in parotid saliva and its ability to bind to HA beads (artificial pellicles), in conjunction with the ability of soluble Fn to inhibit the adherence of streptococcal strains to the artificial tooth pellicles, suggest that the microbial ecology of the oral cavity may, in part, be influenced by the interactions mediated by salivary fibronectin.

Adhesiveness↗
PubMedDate not supplied

A review of esthetic pontic design options.

Advances in the field of restorative materials allow a lost tooth to be replaced by artificial tooth structure that is virtually indiscernible from the original. However, in fixed partial dentures the standards for the pontic area and the adjacent soft tissue in the maxillary anterior region have increased in particular. The pontic design in this region is primarily influenced by esthetic and phonetic considerations. Local defects of the alveolar ridge often complicate restorative measures. Treatment methods proposed to solve this problem involve modification of the pontic design and pretreatment of the recipient site for the pontic. This article reviews the different clinical and technical options that are available for designing esthetic and functional pontics for the anterior region.

Alveolar Process↗