Patent Application
20070106182
The invention relates generally to the field of facial measurement and analysis, and more particularly to a system and method for determining the frontal head posture and measuring the frontal view of the face and underlying hard tissue structures, e.g., such as dentoskeletal structures, and combining such analysis with profile analysis and treatment planning to develop a system and method for full 3D facial analysis.
The study of facial aesthetics is old. Facial attractiveness, while innately recognizable by lay people and artists, has in the past been difficult to quantify. Philosophers and artists have struggled for centuries to identify the concrete structural relationships that create an aesthetically pleasing face. Relationships and proportions for pleasing facial contours are well understood, but only in general terms.
It is understood that facial attractiveness can be defined by at least two main facial characteristics, namely quality of facial parts and position of facial parts. The quality of the eyes, skin, the hair, and lips alter the perception of what is beautiful. Cosmetology and the fashion industry (and to a certain extent medicine by dermatology and chemical skin peels to improve the color, tone, smoothness of the skin) are founded upon improving the quality of these features.
However, the position, shape and size of the facial features arguably have an even greater impact on facial aesthetics. For example, the position, shape and size of the cheekbones, orbital rims, nose, jaws and chin are even more major determinants of facial aesthetics, and surgeons, orthodontists, and dentists are able to affect changes to these facial features using various treatment methods.
Advancements in orthodontics and orthagnathic and craniofacial surgery have led to tremendous advancements in the available treatment for persons with congenital defects, developmental defects, victims of injury and those who simply wish to improve their facial aesthetics. It is known that changes to dentoskeletal structures, such as the teeth, cartilage and bones that underlie soft tissue will greatly influence the outward appearance of the face and head. Accordingly, for example, in orthodontics, the movement of the teeth and jaw line are important in optimizing the frontal and side profiles. While some orthodontists and orthagnathic surgeons are experienced and skillful enough to estimate what changes to the underlying hard structures will result in the most aesthetically pleasing results, for most of these professionals, standards, guidelines and specific directives are greatly preferable and result in more consistently excellent results.
The inventor has in the past developed methods of soft tissue cephalometric analysis for diagnosis and methods for cephalometric treatment planning for aesthetic correction of facial imbalance in a patient with regards to the side profile, both for undifferentiated males and females, and for differentiated male and female groups. See U.S. Pat. Nos. 5,951,498 and 6,200,278, respectively. The disclosures in U.S. Pat. Nos. 5,951,498 and 6,200,278 are incorporated herein in their entirety.
While a good profile is an essential part of good facial aesthetics, it is possible to have a good profile yet still have an overall unbalanced face if the front view has imperfections.
In the past, what has been missing is a method for frontal facial analysis that can be used to ensure that the frontal view of a patient's face is aesthetically optimized. Moreover, by incorporating a method for frontal facial analysis and treatment planning with a method for profile analysis and treatment planning, a person's entire facial balance can be optimized from all views (3D), resulting in an aesthetically pleasing facial appearance from any angle.
There accordingly remains a need for a method for frontal facial analysis that can be used to ensure that the frontal view of a patient's face is aesthetically optimized by a method of combined frontal and profile analysis and treatment planning.
One object of the invention is to provide a method of analysis that focuses on soft tissue landmarks as opposed primarily to hard tissue to achieve consistently excellent outcomes in dental, orthodontic and surgical correction of facial imbalance in frontal view and in frontal plus profile view so that the face and head may be studied in 3D from a variety of angles.
Another object of the invention is to provide health care professionals with a discrete treatment plan to guide in precisely what action must be taken to improve facial balance whether in a frontal view, or frontal and profile views and any other views thereof.
The diagnosis and treatment normal values of the current invention will be carried out by establishing normal size, distance, and angle ranges of various facial landmarks of aesthetically pleasing faces from a population group, and having a patient place his or her head in a natural head position, and correcting that position if necessary, and establishing an anatomical position of the head through which the three perpendicular anatomical planes, namely, the sagittal, transverse and coronal planes will be correlated, and measuring soft and hard tissue landmarks to these anatomical planes to define skeletal and/or soft tissue measurements for the face, and then making orthodontic, dental, and surgical corrections to improve the facial balance and aesthetics as necessary.
In the invention, the frontal head posture and measurements will be used in conjunction with the profile postural head position and measurements in order to create a 3-D model of the face and head.
A frontal and profile head position images will be taken with conventional CT scans, cone beam CT, 3D photography, 2D photography, scattered light photography, laser scanning, profile and frontal cephalometrics, ultrasound and magnetic resonance imaging, or any other imaging technique that presently exists or in the future may be developed.
In order to position the head in the proper anatomical position, it is necessary to properly orient the head with respect to three perpendicular anatomical reference planes, namely the sagittal plane SP, the transverse plane TP, and coronal plane CP. These three anatomical planes of references are shown in
The sagittal plane SP is perpendicular to the floor, runs front to back and up and down. The anatomical sagittal plane is generally utilized to measure the width of the face. The anatomical sagittal plane ASP is a vertical plane that passes through the centerline of the patient's face from front to back, top to bottom, and divides it symmetrically. If the head is properly positioned and balanced, the sagittal plane will pass longitudinally through the centerline of the nose. If a patient tilts his/her chin up or down along the sagittal plane, this will not affect the distances of landmarks to the sagittal plane. However, if the head is tilted to the left or right shoulder, or the head is turned left or right, then the landmarks will move out of alignment with the sagittal plane.
The transverse (or axial) plane TP is a plane parallel to the ground and goes from left to right, front to back. The anatomical transverse plane is generally used to measure the height of the face on the left and right sides. By way of example, when a facially balanced and symmetrical head is in a perfect transverse head position, symmetrical horizontal landmarks on the face and head (e.g., the pupils of the eyes) will lie on the same transverse plane. Turning of the head left to right will not cause the horizontal landmarks on the face and head to be taken out of the transverse plane. In contrast, if the head is tilted to the left or right shoulder, this will affect the distances of the landmarks to the transverse plane TP. If the chin is brought up or down, perpendicularly to the transverse plane TP, this will also affect the distances of the symmetrical landmarks to the transverse plane TP, but equally to both sides.
The coronal plane CP is the vertical plane of reference that is parallel to the front of the patient's face (up and down) and follows from left to right. The coronal plane (CP) is used to measure the projection of the left and right sides, and midline of the face. If the patient's face is facially balanced and properly oriented, the same landmark on the right and left side of the face will be equal distance from the coronal plan CP (see
Since the face is ideally laterally symmetrical viewed from the frontal view, the distances of symmetrically located anatomical features, e.g., the two pupils of eye, from the sagittal plane and from the transverse plane should be the same in a symmetrical and balanced face.
Thus, it can be appreciated that the proper position of the head in the three planes of reference is important in order to create the proper 3-D diagnosis and treatment plan of the head. In order to position the head in the correct orientation, the following exemplary technique may be used. This exemplary technique is representative of the possible techniques that can be used and is not meant to be limiting. Proper posturing is imperative to insure the reliability of any analysis and treatment based on the captured image.
There are three steps to head orientation during imaging and analysis. First, the patient will be asked to look straight ahead into a mirror at his or her pupils and establish a natural head position. In order to do this, the patient will look into a mirror and level his/her head by moving it up and down (bringing the chin up and down) along the sagittal plane. The patient will also turn his or her head from left side to right side along the transverse plane and then look straight into the mirror into his or her own pupils. The patient will also tilt his head from shoulder to shoulder while looking into a mirror to align his head relative to the coronal plane. Carrying out these movements while the patient looks directly into the pupils orients the patient's head into a natural head position.
The natural or postural head position thus established is based on the perspective of the patient looking in a mirror into his or her own eyes. During the process it is important the patients joints are seated, the teeth are at fist contact, and the lips are passively related. The postural head position will thus be oriented in 3-D space relative to the perpendicular sagittal, transverse and coronal planes. The straight ahead vertical and horizontal planes thus established by the patient from his or her own perspective are referred to herein as the “postural sagittal plane PSP”, the “postural transverse plane PTP” and the “postural coronal plane PCP”. However, the postural sagittal plane, the postural transverse plane and the postural coronal plane may or may not in fact be anatomically accurate and could be out of alignment with one or more of the anatomical sagittal, transverse and coronal planes. The postural head position may be altered by postural habits which the patient has acquired or imaging techniques and equipment may make postural head position impossible for the patient to achieve during image procurement.
The second step is to determine the corrected postural position. To make any required corrections, for example, if the practitioner notices that the head is tilted incorrectly relative to one or more of the three anatomical planes, the practitioner can either ask the patient to move his/her head as necessary, or the practitioner can physically move the patients head for him/her. The patient's determined head orientation, including positions in the transverse plane TP, coronal plane CP and sagittal plane SP, may be altered by the practitioner, if deemed necessary, for example as described below, to a corrected transverse plan CTP, corrected coronal plane CCP and a corrected sagittal plane CSP.
Step three is determining the anatomical head position. As used herein, the term “anatomical sagittal plane” ASP is the true (anatomical) midline of the face when viewed from the frontal view. The ASP is used to correct the patient's frontal postural head position after the initial imaging and self-effected positioning conducted by the patient and practitioner adjustments as described above.
As shown in
The patient starts the process in the mirror. This is verified or corrected by the practitioner as necessary and the anatomic sagittal plane ASP can then be applied after imaging is procured. (This process is done this way because some patients are not capable of displaying natural head position because of head orientation habits and imaging equipment and techniques may make it difficult if not impossible for the patient to assume the natural head position.)
Tilting of the head to the left or right shoulder is corrected by constructing the anatomical sagittal plane (ASP). Rotation of the sagittal plane about the axis of the head to the left or right is corrected by equalizing the distance from the left and right pupils to the sagittal plane.
Likewise, as shown in
After orientation of the head via the anatomic sagittal plane and the anatomic coronal plane the transverse plane is established as a perpendicular to the other two planes.
The three anatomical planes (if correction is required), are used in several ways. Herein below, the term “anatomical planes” will be sometimes used to refer to the postural, doctor or operator corrected position or to the anatomical planes. First, the anatomical planes are used to measure the width equality of the left and right sides of the face at a variety of levels (i.e., zygomatic arches or angles of the mandible, etc.) Second, the anatomical planes can be used to measure the distance to the same landmarks (i.e., pupils of the eyes, angles of the mandible, upper and lower canine teeth) on both the left and right sides of the face to determine if these landmarks are on the same level to the transverse plane and/or are perpendicular to the anatomical sagittal plane, or in other words, used to make a measurement of vertical symmetry. Third, the anatomical planes can be used to orient the face for measurement of the height and width and proportionality of those distances. Fourth, the anatomical planes can be used to orient the face for vertical measurement of the face (i.e., upper ⅓ height, upper incisor exposure, etc.) A fifth use of the anatomical planes is to orient the face for a variety of structural measurements (i.e., alar base width [soft tissue], maxillary intercanine width [hard tissue], etc.) As a sixth use, the anatomical planes can be used to orient the face for shape and contour measurements (i.e., cheekbone contour, bridge of nose line).
Key landmarks of the face and head are measured to the anatomical planes. These include some or all of the following:
a. Any hard or soft tissue structures selected by the examining medical professional or other operator. These can include, for example, soft tissue or skeletal angles of the mandible.
b. Vertical structures, for example middle ⅓ of face, upper and lower lip heights.
c. outline structures, i.e., zygomatic arch width, mandibular body width.
d. Structure levels, i.e., eyes, maxillary canines, chin.
e. Midlines structures, i.e., tip of nose, upper incisor midline, and chin.
f. Left and right sides of face, i.e., cheekbone height of contour, angles of mandible.
g. Shape and contour symmetry, i.e., base of nose width, cheekbone contour.
The anatomical planes are also used to orient the face for measurement of any internal structures, such as the base of nose, bony piriform rim, zygomatic buttresses etc.) There are innumerable possibilities which can be measured. Specific measurements would be chosen by the practitioner depending upon specialty.
To facilitate the above measurements, frontal soft tissue and hard tissue facial analysis landmarks are identified using the postural, doctor or operator corrected, or anatomical planes.
Referring again to
In
As an additional method to measure vertical symmetry and facial heights the anatomical transverse plane (ATP) is drawn through soft tissue nasion Na′ ATP-Na′ and is drawn perpendicular to the anatomical coronal plane ACP and the anatomic sagittal plane ASP. The transverse plane TP and anatomical transverse plane through nasion (ATP-Na′) are depicted in
When desired or necessary an appropriate facial landmark identification object or mark can be applied to the skin prior to imaging. The type of identification landmark may be different depending on the type of imaging being used (i.e., cone beam CT, 2-D or 3-D photography, scattered light photography, laser scanning, ultrasound, magnetic resonance imaging and cephalometric x-ray). For example, objects as simple as pen markings or small (e.g., round) adhesive markers which do not distort the imaging modality being used (i.e., metal distorts CT imaging) can be used.
The anatomical sagittal plane ASP, the anatomical coronal plane ACP, and the anatomical transverse plane ATP, as defined above, are perpendicular. By perpendicularly aligning the anatomical sagittal plane ASP (ICD-M to PH-M), and the anatomical coronal plane ACP through subnasale (ACP-Sn), as well as the anatomical transverse plane ATP through Nasion (ATP-Na′) will establish a 3-D reference frame from which all landmarks (both soft tissue and hard tissue) can be identified and measured, which in turn are used to mathematically measure key features of the face and head. These figures will allow an accurate 3D plot of facial landmarks and features to be determined, and therefore will guide health care professionals in treatment planning and execution of facial improvement-procedures, such as orthodontics, orthagnathic and craniofacial surgery. The assignment of the planes to specific landmarks such as the anatomical transverse plane at nasion ATP-Na′ may be altered at the practitioner's discretion if deemed desirable.
To determine the head position relative to the coronal plane (CP) taken from a profile view, patients are assessed clinically according to a modified version of Arnett and Bergman', in natural head position, uppermost condyle, and with passive lips. See Arnett G W and Bergman R T. Facial keys to orthodontic diagnosis and treatment planning. Part I. Am J Orthod Dentofac Orthop 1993; 103(4):299-312; and Arnett G W and Bergman R T. Facial keys to orthodontic diagnosis and treatment planning. Part II. Am J Orthod Dentofac Orthop 1993; 103(5):395-411, the contents of which are incorporated herein by reference.
There are three steps to head orientation during imaging and analysis. First, the patient will be asked to look straight ahead into a mirror at his or her pupils and assumes the postural coronal position (PCP).
The patient starts the process in the mirror. This is verified or corrected by the practitioner as necessary and the anatomic coronal plane ACP (former profile TVL) can then be applied after imaging is procured. (This process is done this way because some patients are not capable of displaying natural head position because of head orientation habits and/or imaging equipment and technique prevent the patient from proper posture.)
The patient will then level his/her head by moving it up and down (bringing the chin up and down) along the sagittal plane. The patient will also turn his or her head from side to side along the transverse plane, and tilt his head from side to side (if necessary, along the coronal plan) and then look straight into the mirror into his or her own pupils. Doing this orients the frontal head posture vertically perpendicular to the floor and from rotating left or right. With the same direction, the profile is simultaneously oriented to profile postural head position. So far, these steps are all taken from the perspective of the patient looking into his or her own eyes.
The second possible step is to establish a corrected postural position. To make any required corrections, the practitioner can either ask the patient to move his/her head as necessary, or the practitioner can physically move the patients head for him/her. The patient's determined head orientation (including the postural profile true vertical line) may be altered by the practitioner, if deemed necessary, for example as described below.
Step three is to determine the anatomical head position. As used herein, the term “anatomical coronal plane” ACP is, defined as a plane which is used to correct the patients profile postural head position after the initial imaging and self-effected positioning conducted by the patient and practitioner adjustments as described above to locate the postural coronal plane or true vertical line (TVL). The anatomical coronal plane ACP is the true profile head position of the face when viewed from the profile view. The line is constructed through subnasale and a point 6-12 mm in front of soft tissue glabella (anterior glabella point). This line is perpendicular to the floor and is the anatomical correction for profile postural head position. The exact position of anterior glabella point within the range is determined by clinical examination of the patient while looking in straight ahead gaze into the mirror.
Table 1 shows various measures from a frontal examination.
Table 1 is just exemplary of some of the measurements that can be taken and is not intended to be limiting in any way.
Although embodiments of the present invention have been described in detail hereinabove in connection with certain exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary is intended to cover various modifications and/or equivalent arrangements included within the spirit and scope of the present invention, as defined in the appended claims.
