Surgery – Diagnostic testing – Measuring anatomical characteristic or force applied to or...
Reexamination Certificate
2000-03-28
2001-07-17
Lacyk, John P. (Department: 3736)
Surgery
Diagnostic testing
Measuring anatomical characteristic or force applied to or...
C378S039000, C382S118000
Reexamination Certificate
active
06261248
ABSTRACT:
This invention relates to a system for use in esthetic dentistry for determining dimensions of maxillary teeth of a person so that the teeth match well his or her features.
BACKGROUND OF THE INVENTION
Cosmetic surgery is for improving a person's feature. One field of the cosmetic surgery is esthetic dentistry for improving the beauty of teeth. Esthetic dentistry improves the appearance of a tooth of a client by appropriate means, such as orthodontics, tooth extraction, putting in of an artificial tooth, moving of a tooth, removing of a portion of a tooth, bonding of prosthetic material to the remaining portion, and bonding of a prosthetic material to the front side or all sides of a tooth.
A reference used in esthetic dental treatment is dimensions of the first incisors in the maxilla. According to a conventional method, the height of the first incisors to be provided by esthetic dental treatment is {fraction (1/16)} of the length of a face, and the width of the first incisors is ¾ of its height. However, the facial length differs greatly from person to person, and the length of the face of a particular person greatly changes as she or he grows older. Accordingly, the determination of an appropriate height and width of the first maxillary incisors on the basis of the facial length is not always successful.
It has been thought to be most desirable to determine the widths of the first incisor, the second incisor and the canine tooth to be in the golden ratio, namely, 1.618:1.0:0.618. On the basis of such conception, sometimes it has been done to combine an image of a row of teeth in the golden section with image of the face of a client to prepare a composite image of his or her face, on which the widths of the teeth can be varied as desired. Then, the client can select the widths of the teeth she or he desires. However, by this method, the widths of the teeth best matching the client's feature cannot always be obtained.
The inventors have determined that the width of the maxillary incisors after the esthetic dental treatment should be determined on the basis of the length of the maxillary denture. When making the invention, the inventors took into account the fact that the length of the maxillary denture is related to the distance between the temporomandibular joints. However, it is difficult to accurately determine these dimensions with equipment installed in common dental clinics. According to the present invention, the distance between the temporomandibular joints is measured indirectly for use in determining the width of the maxillary incisors to be formed by esthetic dental treatment. Also, according to the present invention, dimensions of other teeth to be formed are determined on the basis of the determined width of the maxillary incisors.
SUMMARY OF THE INVENTION
According to a first embodiment of the present invention, the distance between the pupils of a client is measured by pupillary distance measuring means, and the measurement a is inputted into dimension determining means. The dimension determining means determines the dimensions of maxillary incisors from the measured pupillary distance &agr;. It may do the following computations to determined the width W1 and the height H1 of the first incisors.
W1=&agr;×2.5×({fraction (1/16)}) (1)
H1=W1×({fraction (4/3)}) (2)
The width W2 of the second incisors and the width W3 of the canine teeth are determined by the following equations in accordance with the golden section.
W2=0.618W1 (3)
W3=0.618W2=0.618
2
W1 (4)
An image of the face or its portion of the client is displayed on image display means. The image may be obtained by still image photographing means, e.g. an ordinary camera or a digital camera. An image of teeth having the temporarily determined dimensions as determined by the dimension determining means is displayed on the display means together with the image of the face or its portion. The position of the image of the teeth on the display means can be moved as desired, by display control means. For example, the image of the temporarily determined teeth can be superposed on the teeth in the photograph of the client's face. The dimension determining means and the display control means may be provided by, for example, the electronic computer, and the image display means may be a monitor associated with the computer. The pupillary distance measuring means may be ophthalmic scale or a spectacle adjustment optical meter. Alternatively, it may be realized by pointing the pupils displayed on the monitor by pointing means, e.g. a pointing device, and computing the distance between the pupils by the computer.
In esthetic dentistry, it is known to employ the height of first maxillary incisors which is equal to {fraction (1/16)} of the length of a face as measured between the vertex and the tip of the lower jaw orthogonally projected onto a vertical plane, and the width which is equal to ¾ of the height. The values “{fraction (1/16)}” and “¾” are for standard features. Since the ancient Greece, the width of an ideal face has been considered to be ¾ of the length of the face. It is also known medically that the ideal pupillary distance is {fraction (1/2.5)} of the ideal face width. Accordingly, the ideal feature includes a face width which is 2.5 times as large as the pupillary distance &agr;, a face length which is {fraction (4/3)} times as long as the pupillary distance &agr;, and a maxillary incisor height H1 which is {fraction (1/16)} times as large as the pupillary distance &agr;. Accordingly, the first incisor height H1 can be expressed as:
H1=&agr;×2.5×{fraction (4/3)}×{fraction (1/16)}
The width W1 of the first maxillary incisors can be expressed as follows.
W1=¾×H1=&agr;×2.5×{fraction (1/16)}
As stated previously, the most important factor in determining the width of maxillary incisors is the distance between temporomandibular joints. The temporomandibular joint distance is dependent on the width of a cranium at the level of orbits. The orbits occupy almost the entire width of the cranium. The pupils are at the centers of the respective orbits. Accordingly, the temporomandibular joint distance can be known from the measured pupillary distance. Accordingly, the proper dimensions of the maxillary incisors can be determined without resort to a conventionally employed reference, e.g. the face length, which differs from person to person and also changes with age.
If the computed teeth dimensions do not fit the maxilla of the client in the displayed image, they can be modified on the display by means of the display control means through the pointing means. Usually, the amount of modification is within a range of from about −3% and to 0%, and does not go outside a range of from −10% to +3%. One or more of the above-described dental techniques are chosen for the treatment.
According to another embodiment of the present invention, a maxillary tooth dimension determining system may be realized, which can determine the thickness of maxillary teeth to be shaped. According to this embodiment, bottom still image information prepared by obtaining an image of a portion to be treated of a maxillary denture of a client from below by still image photographing means. At least right and left first and second incisors and right and left canines, for example, should be in the image.
The pupillary distance of a client is measured by pupillary distance measuring means, and information representing the measured pupillary distance is inputted into dimension determining means, which computes a temporarily determined width of the portion to be treated. The temporarily determined width may be, for example, the sum of at least the right and left first and second incisors and the canines. Display control means causes an image to be displayed on image display means. The displayed image is a bottom image of the portion of an ideal
Furuoka Shingo
Takaishi Yoshitomo
Duane Morris & Heckscher LLP
Lacyk John P.
Takaishi Yoshitomo
Wingood Pamela L.
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