WO1997034278A1

WO1997034278A1 - Dental models

Info

Publication number: WO1997034278A1
Application number: PCT/AU1997/000148
Authority: WO
Inventors: Frank Hunter
Original assignee: Frank Hunter
Priority date: 1996-03-12
Filing date: 1997-03-11
Publication date: 1997-09-18
Also published as: AU2087397A; AUPN863596A0

Abstract

A dental model comprising three components, a first component being substantially rigid and formed so at to simulate at least one tooth having crown and root, a second component being substantially rigid or semi-rigid formed so as to simulate bone, and a third component being formed so as to simulate gingiva and associated soft tissue, wherein the second component having a recess adapted to accommodate the first component via the root and the third component having a recess to accommodate the second component in a position simulating the respective positioning of tooth, bone and gingiva in an animal.

Description

Dental Models

Technical Field

The present invention relates generally to dental models and particularly to models adapted to demonstrate the various anatomical relationships that may exist between teeth and their supporting structures.

Background Art

Teeth are supported in the mouth by their roots being attached to bony sockets through a supporting means comprising a network of periodontal fibres. This supporting means is surrounded on the uppermost limits by the gingiva. The entire supporting apparatus consists of tooth, root, cementum, bone, periosteum, periodontal fibres, connective tissue, blood vessels, nerves and gingival tissues. This complex support apparatus which is attached to the tooth is collectively referred to as "the Periodontium". Although many of these components are microscopic, collectively they form a definitive structure and anatomical relationship and are important in clinical health. During the very first stages of disease processes, any one of these relationships may change and the degree of disease present in this tissue may be reflected in the degree of change in this relationship.

While there exists various dental models to demonstrate certain aspects of teeth and their supporting structures, veiy few effectively demonstrate the basic clinical criteria that are relevant to periodontal health or disease. Many of the present models have limited use in demonstrating the various clinical and anatomical relationships that can exist between teeth and their supporting structures at or during various stages of periodontal health and disease processes. Moreover, some of the existing models are rather complex, expensive and confusing.

There is the need for dental models that are adapted to demonstrate essential clinical criteria and important anatomical relationships that exist between teeth and their supporting structures in both periodontal health and various stages of periodontal disease. Dental models are needed that are particularly useful in communicating and demonstrating to dentists, dental hygienists, dental auxiliaries, dental personnel, dental technicians, dental students, dental salespersons, dental patients and to general audiences the anatomical relationships of teeth and their supporting structures in both the state of clinical health and the various stages of periodontal disease. Furthermore, with the rapid progress in periodontal research, the evolution of new techniques and the development of new diagnostic dental probes as found in US patent Nos 5137447 and 5322437, there is a need for dental models which reflect these scientific advances, represent clinical reality and which are therefore more suitable to demonstrate the advantages of these new probes and procedures over existing instruments and techniques. New dental models are also needed to teach dental personnel improved methods in diagnosis and treatment modalities using these new instruments, techniques and procedures. Scientific research worldwide has shown that periodontal disease is essentially an inflammatory response to a foreign material irritant. Most commonly, this irritant is dental plaque, which is a naturally occurring host generated mix of saliva, food, mucins, microorganisms and other matter. Plaque commonly exists on teeth and gums as a sticky mass which slowly grows if not removed. Plaque can eventually "calcify" through the process of mineralisation and thus form the substance referred to as "calculus", or, more commonly as "tartar". Once this calcification process has commenced, it may continue and thus form a growing mass of calculus. Since the initial offensive agent is plaque and this may be rather soft, and as this undergoes progressive mineralisation and calcification, the degree of hardness or calculus maturity is often a reflection of the longevity of the process, to the point that calculus may exist as a thick soft material, or any stage of consistency through to hard, brittle mature calculus. This matter can attract the deposition of more plaque, and the process may continue resulting in advance in the dental disease state until ultimate loss of tooth or teeth, or alternatively, intervention by professional debridement or other treatment modalities. Intervention commonly includes initial plaque removal (or prophylaxis), primary debridement (or scaling) and secondary debridement or root surface smoothing (root planing). During the initial inflammatory response to deposits of plaque, the tissues surrounding the tooth become swollen, soft, red and sometimes painful. If the growth of plaque is allowed to continue, it may accumulate in mass and eventually calcify. The inflammatory response to this process may continue accordingly and this may eventually lead to tissue breakdown. This, in turn, may result in alteration of the anatomical relationships between the many tissues involved in the complex attachment apparatus referred to as "the periodontium".

Since dental plaque has been discovered to be the common causative agent to both dental caries and periodontal disease, any feature on the tooth surface which is plaque retentive will predispose that tooth to dental disease.

These aetiological factors include any surface roughness which tends to retain plaque at any site and includes dental calculus, defective restoration margins, root caries, root erosion, root damage and any surface resistance on the tooth or periodontal apparatus. There is a need to be able to demonstrate the presence and effect of these aetiological factors and causative agents on a dental model to be able to demonstrate the initial and more subtle changes to the anatomical relationships of the various tissues involved. As the disease process continues, there is need for dental models that are able to demonstrate the more progressive and destructive changes to the relationships of these tissues. Furthermore, as the disease may proceed further, there is a need for dental models that demonstrate the relationship of all these features as they pertain to diagnostic and treatment modalities in the clinical situation. The present inventor has been involved in much of the recent periodontal research, is aware of the actual clinical realities, and has developed dental models which represent more precise and appropriate clinical detail of the various anatomical and clinical relationships that may exist between teeth and their supporting structures in both periodontal health and different stages of periodontal disease. These models are useful in demonstrating these clinical features to patients and to all dental personnel, irrespective of their intellectual climate, professional status, profile or portfolio. Disclosure of Invention

The dental models of the present invention are particularly suitable for demonstrating to dental workers, dental salespersons and to patients the anatomical relationship between tooth, bone and gingiva (and associated soft tissue). The models are also useful to demonstrate the region of these components that are prone to dental disease.

In a first aspect, the present invention consists in a dental model comprising a first component being substantially rigid and formed so as to simulate at least one tooth having a crown and root, and an element or elements adapted to simulate at least one aetiological factor in periodontal disease, the element or elements being positioned on or in the first component so as to simulate one or more factors causing dental disease.

Preferably, the element or elements are adapted to simulate any one, any combination, or all of the aetiological factors selected from the group consisting of dental plaque, calculus, defective restoration margins and root surface roughness of any kind.

The dental model according to the first aspect of the present invention comprises a tooth component and an element or elements adapted to simulate at least one aetiological factor in periodontal disease being positioned on or in the tooth component so as to simulate its clinical existence and consistency.

As the consistency of dental plaque and dental calculus varies considerably, there is a range of materials used for its effective clinical simulation on the present dental models. The range of materials suitable for the element or elements of the first aspect of the present invention is described as follows:

Plaque:

Synthetic plaque comprises any single component or mix of materials such as silicone, wax, syrup, gelatine, gums, glues or gels of any kind or any other material representative of authentic dental plaque and applied on the tooth component of the dental models.

Calculus:

Synthetic dental calculus may be prepared from any single compound, particulate matter or any mix of materials representative of the varying degree of consistency that authentic dental calculus may clinically exist. The materials suitable include materials derived from metallic, mineraline. organic, synthetic, chemical, plastic or resin bases, such as metal shavings, aluminium oxide, sand, silica, glass, quartz, plastic, acrylics, methylacrylates or any other such matter.

Generally, the particulate matter in an element in the form of synthetic calculus suitable for the dental models should range in size from 10 microns to 1000 microns, ideally having a 50-500 micron range. The material is applied to the tooth component to represent the varying degrees of mineralisation found clinically in authentic dental calculus.

Combination: As the ratio of dental plaque relative to that of calculus may vary in the clinical situation, the ratio mix of the synthetic substances may also vary on the tooth component to mimic the authentic situation. The precise elements, consistency and choice of material will also vary on the dental model according to the aspect and purpose of the demonstration. The model may be used to show the presence of these substances, to provide exercises in clinical detection, diagnostic determination, quantification and qualification, clinical assessment techniques, various treatment modalities and debridement procedures or any combination thereof. The composition of the simulating material may consist of any sized particulate matter to more effectively represent the consistency, feel and form found in the vast ranges of authentic dental plaque and dental calculus. Similarly, the adhesive means of positioning synthetic plaque and/or calculus to teeth or periodontal tissue component of the present dental models may include any glue in a range of adhesive materials such as cyanoacrylate epoxy resins, gums, glues or gels of any kind. Defective Restoration Margins:

The present dental model having a tooth component may also include material, in any position on or in the tooth component, which demonstrates the clinical presence or effect of a defective restoration margin. This may be over or under contoured and may include any catch, ledge or surface interference. The material used may include dental restorative material such as amalgam, composite resin, glass ionomer, any cement, synthetic resin, metal, acrylic or any other material. Root Surface Roughness:

The root and crown surfaces of the tooth component of the model should preferably closely simulate that surface integrity of natural teeth. There is a difference between enamel (of the coronal portion) and cementum or dentine (of the radicular portion) of any tooth and this may be represented in the present dental models to allow the demonstration of clinical aspects of clean, healthy natural teeth. Also various degrees of tooth surface roughness which may exist on the tooth component of dental models may be provided in the form of dental caries, root caries, root erosion, mechanical damage and general alteration from that of natural, clean, healthy teeth. These roughness phenomena can be applied by use of mechanical means such as applying any abrasive material including sandpaper, particle blasting, drills, burrs, knives, files or using any other utensil. Any chemical means such as etching, gluing, or other treatments and any biological means that may also be used.

In a second aspect, the present invention consists in a dental model comprising two components, a first component being substantially rigid and formed so as to simulate at least one tooth having a crown and root, and a second component being substantially rigid or semi-rigid formed so as to simulate bone, wherein the second component has a recess adapted to accommodate the first component via the root.

In a third aspect, the present invention consists in a dental model comprising three components, a first component being substantially rigid and formed so as to simulate at least one tooth having a crown and root, a second component being substantially rigid or semi-rigid formed so as to simulate bone, and a third component being formed so as to simulate gingiva and associated soft tissue, wherein the second component having a recess adapted to accommodate the first component via the root and the third component having a recess to accommodate the second component in a position simulating the respective positioning of tooth, bone and gingiva and associated soft tissue in an animal.

In a preferred embodiment of the second or third aspects of the present invention, the first component is formed so as to simulate a healthy tooth or teeth or comprises the dental model of the first aspect of the present invention wherein the tooth component includes at least one element simulating an aetiological factor in periodontal disease.

Preferably the second component of the model is a simulation of bone and in particular the bone tissue surrounding the tooth. The second component may be in a rigid or semi-rigid form or be made in a combination of these two forms. In a preferred embodiment, the second component is opaque, clear, translucent or any combination thereof so as to allow visualisation of the tooth component in the bone component. In a further preferred embodiment, the topographical contour of the uppermost bone height relative the tooth will vary on the models as it varies in the clinical situation relative to the state of health or the stage of disease present.

In an other preferred embodiment of the third aspect of the present invention, the component that simulates the gingiva and associated soft tissue is semi-transparent so as to allow the visualisation of the positioning of the tooth component and bone component within the gingiva component. More preferably, the component simulating gingiva and associated soft tissue has resiliency similar to authentic gingiva and associated soft tissue.

The three components may be separate and engageable, or be formed in a combination of one or more of the components. For example, the tooth and bone component may be formed together with the gingiva component separate and engageable with the other two components.

It will be appreciated that the dental models of the second and third aspects of the present invention may comprise one tooth within a bone segment having gingiva and associated soft tissue surrounding the tooth and bone or may comprise any number of teeth up to a full model comprising complete set of teeth, bone and gingiva and associated soft tissue. The models may be formed to mimic a healthy situation or any diseased situation found in animals.

The dental models of the present invention are particularly useful in periodontics as they can be formed to mimic accurately the natural situation in animals.

In order that the nature of the present invention may be more clearly understood, preferred forms will be described with reference to the following examples and drawings: Brief Description of Drawings

Figure 1 is a perspective view of a dental model according to the present invention in an assembled form;

Figure 2 is an exploded perspective view of a dental model according to the third aspect of the present invention; Figure 3(a) is a perspective view of a dental model according to the first aspect of the present invention showing positioning of examples of aetiological factors on a tooth;

Figure 3(b) is a perspective view of a dental model according to the second aspect of the present invention showing positioning of different bone heights and furcation lesions; and

Figure 3(c) is a side view of a dental model according to the first aspect of the present invention showing positioning of further examples of aetiological factors on a single rooted tooth. Modes for Carrying Out the Invention Figure 1 shows an assembled dental model (10) comprising a tooth component (11) having a crown (12) and root (13); a bone component (15) having a recess (16) therein and a gingiva component (17) having a recess (18) therein to accommodate the tooth and bone components (11, 15).

In a preferred form the dental models comprise three components that are engageable to form a complete model of tooth, bone and gingiva (Figure 2). The tooth component (11) is locatable via the root (13) in the recess (16) of the bone component (15) and furthermore the bone component (without or without the tooth component) may be accommodated within the recess (18) of the gingiva component (17). The tooth component (11) may also contain components to simulate aetiological factors of dental disease (14) (Figures 3(a) and (c)). These components (14) may be located on the root

(13) or anywhere else on the tooth component.

The bone component (15) may be in a form to simulate "healthy" bone or alternatively be in a form to simulate "diseased" bone to show the effects of dental decay and disease. Similarly, the gingiva component (17) may be in a form so as to simulate "healthy" gingiva or alternatively in a form to simulate "diseased" gingiva.

The topographical contour (19) of the uppermost bone height on the relative to the tooth may vaiy on the dental models as it varies in the clinical situation, relative to the state of health or the stage of disease present (Figure 3(b)). The bone height from the cemento-enamel junction on the tooth should measure from between 0-10 millimetres. Specific bone height pockets exist at least at 2, 4 and 6 millimetre depths from the cemento-enamel junction.

The bone component can be a creamy (bone) colour throughout, coloured only at the uppermost periphery (at, say, up to 1 mm deep) and be clear throughout so as to allow visualisation, or be totally clear throughout. The material can be rigid, as in an acrylic, plastic or resin material, it can be semi-rigid, as in a silicone or resin material or it may exist in any combination of these forms. All variations are possible so as to represent the clinical features apparent in the mouth according to various types of tissue integrity. Since natural healthy teeth are supported in a rigid bony socket by a layer of softer periodontal fibres, one preferred embodiment is to have a layer of softer material, such as silicone or plastic laying between a rigid surface layer of the bone component and the tooth component. Since this horizontal relationship continues even during the disease process and in spite of vertical tissue loss, this feature may be made continuous around the circumference of the tooth, or be localised at any site or number of sites around the tooth. As the width of the periodontal fibre network may be very small in clinical health, another embodiment does not have any intervening material between the bone component and the tooth component. Another feature of the dental models is to demonstrate the phenomenon known as a "furcation" lesion. This is represented by a "tunnel" existing through the bony zone between the roots on a tooth with more than one root. This tunnel may be complete and thus continue from one side of the tooth right through and appear at another site on the same tooth. This is seen in "division III" lesions. Alternatively, the tunnel may be partial and thus finish in the area between the roots. This is seen in "division I and II' furcation lesions.

The gingiva component may be substantially rigid or of a resilient material which simulates the status of authentic clinical tissue. The gingiva component may be either translucent or transparent to better visualise the underlying structures. The gingiva component may be completely removable, partially removable, or attached in any way to the bone component. The removable form has certain detail within it which corresponds to similar detail in the bone component of the dental model and so serve as a positive orientator when re-locating the gingiva component on the model. This locater detail can be in any male/female or positive/negative format that is appropriate. The gingiva component may be made from any plastic, silicone, resin, polymer or any other material which simulates gingiva. It may be coloured or clear and lubricated or moist to simulate oral epithelium and gingiva.

It will be understood by one skilled in the art that the dental models may comprise one tooth having plaque retentive features or other features simulating aetiological factors of dental disease, or a tooth with surrounding gingival tissue and bone, or a tooth within a bone segment. Alternatively, the model may comprise any number of teeth up to a full mouth model comprising a complete set of teeth, with any number exhibiting plaque retentive features, jaw bone and gingiva. The models may be so formed as to mimic a healthy situation or any diseased state that may be found in humans or other animals. The dental models so described are of particular use in periodontics. The dental models have a further advantage that they allow the demonstration of general dental practices including detection, measurement and diagnostic methods using dental probes and also be used for demonstrating treatment of pathological states. The dental models according to the first aspect of the present invention are particularly useful to demonstrate tools applicable for the diagnosis and treatment of dental calculus on teeth.

The dental models may be used to instruct dental practitioners including dentists, dental students, dental hygienists, dental technicians and the like in the emerging diagnostic and treatment procedures. Similarly, the models are particularly suitable for use by dental instrument salespersons to demonstrate new products and procedures to dental clients. Importantly, the dental models are particularly suitable for demonstrating to the uninformed public, either patients or health workers, the types and effects of periodontal disease relating to teeth, bone and gingiva and may be useful to assist in preventative care education.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A dental model comprising a first component being substantially rigid and formed so as to simulate at least one tooth having a crown and root, and an element or elements adapted to simulate at least one aetiological factor in periodontal disease, the element or elements being positioned on or in the first component so as to simulate one or more factors causing dental disease.

2. A model according to claim 1 wherein the element or elements are adapted to simulate any one, any combination, or all of the aetiological factors selected from the group consisting of dental plaque, calculus, defective restoration margins and root surface roughness.

3. A dental model comprising two components, a first component being substantially rigid and formed so as to simulate at least one tooth having a crown and root, and a second component being substantially rigid or semi- rigid formed so as to simulate bone, wherein the second component having a recess adapted to accommodate the first component via the root.

4. A dental model comprising three components, a first component being substantially rigid and formed so as to simulate at least one tooth having crown and root, a second component being substantially rigid or semi-rigid formed so as to simulate bone, and a third component being formed so as to simulate gingiva and associated soft tissue, wherein the second component having a recess adapted to accommodate the first component via the root and the third component having a recess to accommodate the second component in a position simulating the respective positioning of tooth, bone and gingiva in an animal.

5. A dental model according to claim 3 or 4 wherein the first component being formed so as to simulate a healthy tooth or teeth.

6. A dental model according to claim 3 or 4 wherein the first component comprises the dental model according to claim 1 or 2.

7. A dental model according to any one of claims 3 to 6 wherein the second component being a simulation of bone tissue surrounding the tooth.

8. A dental model according to claim 7 wherein the second component is opaque, clear, translucent or any combination thereof so as to allow visualisation of the tooth component in the bone component.

9. A dental model according to any one of claims 3 to 8 wherein the third component simulating gingiva and associated soft tissue is semi- transparent or transparent so as to allow the visualisation of the positioning of the tooth component and bone component within the gingiva and associated soft tissue component.

10. A dental model according to claim 9 wherein the component simulating gingiva and associated soft tissue has resiliency similar to authentic gingiva and associated soft tissue.

11. A dental model according to any one of claims 3 to 10 wherein the components are engageable.

12. A dental model according to any one of claims 3 to 10 wherein two or more of the components are formed together.