Abstract:
A gauge for measuring and/or marking teeth or models of teeth for the determination of the placement of attachments for orthodontic braces. The gauge has a first arm with a gauge element with a longitudinal extension portion lying on a first axis and a vertical extension portion extending generally perpendicularly from the first axis of the longitudinal extension portion. The gauge has a second arm which has a pointer or marking element at an end thereof, the pointer element having a tip which is spaced apart from the longitudinal extension portion of the first arm, the first and second arm being connected together to maintain the spaced apart relationship between the tip of marking element and the longitudinal extension portion with the vertical extension portion extending towards the pointer or marking element. The invention also provides a gauge element for converting a bow divider into a gauge for measuring and/or marking teeth for the determination of the placement of attachments for orthodontic braces. The gauge element has an elongate extension portion lying on a first axis and a vertical extension portion extending generally perpendicularly to the first axis of the elongate extension portion with the vertical extension portion extending outwardly between about 2.00 mm and 3.00 mm from the longitudinal extension portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]    This applications claims priority based upon provisional patent application No. 60/263,493, filed Jan. 23, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The invention is in the field of measurement gauge that is used to assist in accurately placing the braces (individual attachments primarily composed of brackets and tubes) onto the upper and lower teeth on an orthodontic patient.  
           [0003]    Presently, all measurement gauges used to position attachments on teeth function by making a linear measurement from the edges or cusp tips of all anterior (front) or posterior (back) teeth on the labial (lip) or buccal (cheek) side of the individual teeth toward the gingival (gum). This measurement is at a set distance from these landmarks i.e. cusp tips and biting edges of all teeth. Due to the anatomic variation in the height of cusps of posterior teeth, random wear patterns, and occasional cusp fractures, this method has numerous shortcomings in accuracy.  
           [0004]    In reality, the orthodontist wants to position the attachments on all teeth so that the marginal ridges of the posterior teeth (the biting surface peripheral ridges located on the interproximal or side of the tooth) line up next to adjacent teeth in height. The marginal ridges should line up with little or no individual tooth marginal ridge variation in height to achieve the correct position of both upper and lower posterior teeth in order to allow opposing teeth to fit together when a person bites (or occludes) their teeth together.  
           [0005]    The attachments on the posterior teeth should initially be positioned on each tooth so that when a straight wire (bent in the shape of an upper or lower dental arch of teeth) is engaged in the brackets and tubes, the teeth being adjusted will eventually be ideally aligned one to the other in either an upper or lower dental arch, and when the opposing teeth are brought together in a neutral bite, they occlude (fit together) ideally.  
           [0006]    There accordingly remains a need for an accurate and easy to use gauge for measuring and/or marking teeth of an orthodontic patient for placement of braces thereon.  
         SUMMARY OF THE INVENTION  
         [0007]    The invention provides a gauge that ideally accomplishes the need to measure and/or mark teeth easily and accurately so that braces can be correctly placed on the teeth in the ideal occluso-gingival position.  
           [0008]    The invention provides a gauge with two arms. The first arm has two measuring axes. The first axis, (axis A) extends longitudinally along the long axis of the first arm and is used to measure the anterior teeth, i.e. the upper or lower cuspids and incisors. A vertical extension  38  is attached at a right angle to axis A and lies along an axis B, and the vertical extension  38  is typically rested on the mesial (the one closest to the front of the mouth) marginal ridge of a posterior tooth with axis A perpendicular to axis B and held parallel to the long axis of the tooth. The second arm of the gauge carries a pointed element, which may include an assortment of marking means, including but not limited to a pencil lead, washable inks delivered through a fine point, a grease pencil marker, or other known marking means or a non-marking means. The key element or measurement of the difference between axis A and the vertical tip of the axis B is approximately 2.5 mm with a variation of about 0.50 mm for most patients.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a cheek side view showing a quadrant of a patient&#39;s teeth with bands, brackets and an arch wire in the brackets.  
         [0010]    [0010]FIG. 2 is an occlusal (biting) surface view of the upper bicuspid and first molar.  
         [0011]    [0011]FIG. 3 is a side view of an embodiment of the gauge of the invention.  
         [0012]    [0012]FIG. 4 is an enlarged view of the front end of the gauge of FIG. 3.  
         [0013]    [0013]FIG. 5 is an interproximal view of the upper central incisor with the gauge of FIG. 3 in place.  
         [0014]    [0014]FIG. 6 is an interproximal view of the upper bicuspid with the gauge of FIG. 3 in place.  
         [0015]    [0015]FIG. 7 is a side view of the buccal and labial surfaces of the upper right quadrant of a patient teeth, with marks made by the gauge.  
         [0016]    [0016]FIG. 8 is a front view of a patient&#39;s mouth from the lip side showing six upper anterior teeth with attachments mounted to the teeth and a straight archwire segment.  
         [0017]    [0017]FIG. 9 is a front view of a patient&#39;s mouth from the lip side showing six lower anterior teeth with attachments mounted to the teeth and a straight archwire segment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    [0018]FIG. 1 is a side view showing a quadrant of a patient&#39;s teeth (viz. the second molar, first molar, second bicuspid, first bicuspid, cuspid, lateral incisor, and central incisor) with bands  10  with molar tube  12  and brackets  14  mounted thereto. A segment of an archwire  16  is shown positioned in slots  18  of the brackets and in the molar tube  12 . The teeth&#39;s incisal edges and cusp tips are shown.  
         [0019]    [0019]FIG. 2 is a view of the upper bicuspid and first molar view from the occlusal (biting) surface showing the cusp tips and marginal ridges thereon.  
         [0020]    [0020]FIG. 3 is a side view of an embodiment of the gauge  30  of the invention. Gauge  30  has arms  32  and  34 . Arm  32  has a gauge element  28  which has first longitudinal extension  36  which lies on a first axis A, and is used to measure the anterior teeth, i.e. the upper or lower cuspids and incisors. A vertical extension portion  38  is affixed to longitudinal extension  36  on a second axis, (axis B) which is preferably generally at a right angle to longitudinal extension  36  and axis A and is perpendicular to the opening and closing axes of the arms of the gauge. Vertical extension portion  36  is typically used by being rested on the mesial marginal ridge (the one closest to the front of the mouth) of a posterior tooth with axis A perpendicular to axis B held parallel to the long axis of the tooth. Second arm  34  of gauge carries a pointer element  40 , which can be either a marking element, or a non-marking element. Marking element  40  can be chosen from any number of marking means, including but not limited to a pencil lead, washable inks delivered through a fine point, a grease pencil marker, or other known marking means, and non-marking element can be a metal scriber, for example. Pointed marker  40  has a pointed tip  50 . Pointer element  40  (if in the form of an elongate pencil lead or an elongate scriber, for example) is preferably retained in second arm  34  in a position generally parallel to axis A of first arm  32 . If the operator prefers a non-marking element, a pointed element may be used to measure the accuracy of the attachment placement. In order to provide for longitudinal adjustability of longitudinal extension  36  in first arm  32  and pointer element  40  in second arm  34 , tension means  42  and  44  (e.g. thumbscrews) can be utilized. Although gauge  30  is shown in the general form of an arc drawing compass or bow divider with an adjustment knurl and screws  46  to (vary preferably continuously) the distance between the arms, the arms  32  and  34  could be set apart in a static and unadjustable orientation. Gauge element  28  can be provided as a separate part which can be used with standard dividing bows (which has been modified to provide for proper parallel orientation of the marking element (or non-marking element) and the gauge element on the arms) in place of the standard sharpened prong to convert standard dividing bows into gauges of the invention.  
         [0021]    [0021]FIG. 4 is an enlarged view of the front end of the gauge  30  of FIG. 3. Longitudinal extension  36  has a tip  52 , and vertical extension portion  38  extends from longitudinal extension  36 . Vertical extension portion  38  has a length of about 2.5 mm with a variation of about plus or minus 0.50 mm for most patients. Longitudinal extension  36  preferably has a first visual guide mark  54 , a second visual guide mark  56 , and a third visual guide mark  58 , all spaced apart from each other. Vertical extension  38  has a forwardly facing surface  38 A and a rearwardly facing surface  38 B. Vertical mark  58  is used as a guide to determine the degree to which it is inserted into first arm  32  to the degree to which it extends forwardly of a tip  60  of first arm  32 . If the longitudinal extension is permanently affixed or unitary with first arm  32 , no third marking  58  is needed. The visual guide marks are used as an aid to help position the point  50  of pointer element  40  in a forward or backward position, depending on whether anterior or posterior teeth are being measured and marked. The feature of the gauge to permit the marking element  40  to slide longitudinally forward and backward in arm  34  provides a function so that when the gauge is first positioned on the tooth to be measured the marker may slide forward to place the mark on the tooth at the correct place. Tip  52  is distance A away from vertical extensionp&#39;s forwardly facing surface  38 A and vertical extension&#39;s rearwardly facing surface  38 B is spaced distance B from the rearwardly lying second guide mark  56 . Distances A and B are preferably about  3  mm plus or minus 1.0 mm and is ideal for most patients. First and second arms  32  and  34  are preferably spaced apart a sufficient distance D such as to provide for the required spacings of the arms so that longitudinal extension  36  and pointer element  40  are preferably parallel or close to parallel. This necessitates modifying a typical bow divides to achieve this parallelism. The projection of tip  50  of pointer element  40  can be adjusted to abut a vertical projection line E from the centerline of vertical extension  38  and first guide mark  54  or to abut a vertical projection line F projecting vertically downwardly from second guide mark  56 . In either case, vertical extension  38  has a distal tip  62  that is spaced apart from marking element  40 .  
         [0022]    The use of the gauge is best described with reference to FIGS. 5 and 6. The operator first determines on a selected tooth (typically a first molar) where the attachment should be ideally positioned. The user uses gauge  30  to measure the correct vertical distance to position the tube or slot of the bracket on the tooth. On lower teeth, the attachments should be placed low enough on the buccal surface of the clinical crown toward the gingival, to avoid traumatic occlusion, i.e. upper teeth striking the attachment before full closure and contact of opposing teeth are effected. On the upper teeth, the attachments are usually positioned near the center of the typical clinical crown occluso-gingivally. For use in marking an upper tooth, (e.g. an upper central incisor), as shown in FIG. 5, the user will place longitudinal extension  36  so that it rests on the incisal edge of the upper central incisor with vertical extension  38  resting on a front of the tooth. With the axis A of longitudinal extension  36  at a right angle (or generally right angle) to a long axis of the tooth (with axis B of vertical extension  38  being parallel or generally parallel thereto, tip  50  of pointer marking element  40  (if it is a marker element) is used to mark the interproximal surface (front) of the tooth.  
         [0023]    Once the gauge is set at the correct height for the attachments to be placed, for example on the upper teeth, it remains set at that height while all the teeth of the upper arch are measured and marked, as shown in FIGS. 5 and 6. The mark is placed near the interproximal of each tooth so that the attachment may be affixed to the tooth using the mark as a reference guide. In the case of marking a bicuspid, FIG. 6 shows the use of the gauge to mark an upper bicuspid, wherein vertical extension  38  is placed in contact with the marginal ridges and is held with its axis B held generally parallel to the long axis of the tooth, and with the longitudinal extension  36  and its axis A generally perpendicular to the long axis of the tooth. Held as such, pointed tip  50  of marking element  40  can be used to place a mark on the face of the tooth.  
         [0024]    [0024]FIG. 7 shows the teeth to which bands or brackets will be attached thereto after being marked with marks  70   a,    70   b,    70   c  . . .  70   g.  The marks thus made are not covered at this time by the attachments and serves as a constant guide for placement. In certain situations, the interproximal gingival papilla may be marked instead of the tooth and may be used as the reference mark. When the operator wishes to set the height of the attachments for the lower teeth, it may be at a different height setting than the upper, but as in the case of the example of marking the upper teeth, remains the same setting while the lower teeth are marked.  
         [0025]    Due to anatomic variations and functional characteristics of the upper and lower front teeth, slight adjustments of the vertically marked positions by the gauge may be necessary. Indeed, regarding the upper anterior teeth, the position set and marked by the gauge is used to position the cuspids and central incisors. The lateral incisors typically need to be offset by one half to one millimeter. Offset means that the incisal edges of the lateral incisors are placed one half to one millimeter toward the gingival from a line passing through the central incisal edges and the cuspid tips, which is shown in FIG. 8. To do this, the mark originally placed on the lateral incisors when the gauge is used, is moved one half to one millimeter closer to the incisal edge of these teeth. The effect, when a straight wire is passed though the bracket slots of the upper six anterior teeth, is to offset or raise the lateral incisors relative to the cuspids and central incisors and ideally position these lateral incisors both cosmetically and functionally. With regards to the lower anterior teeth, the gauge position set and marked for the lower arch is used in the anterior for the cuspids only. All four lower incisors typically need to be stepped down (gingivally) approximately one half to one millimeter, as shown in FIG. 9. To do this, the mark originally placed on the four incisors is moved incisally, away from the gingival approximately one half to one millimeter. The net affect positions the lower anterior teeth ideally, both cosmetically and functionally.  
         [0026]    To reiterate, this gauge is unique in that once set for a particular arch, it measures the height for placement of an attachment on each tooth in relation to the edges of the anterior teeth with adjustments to these teeth previously described. That same measurement is in harmony with the correctly marked height of the posterior teeth, with the marginal ridges as a measurement point, (using the tip of axis B) and the opposing marking element of the gauge to mark the teeth.  
         [0027]    The marking system of the gauge is also unique in that it leaves a very small mark or dot near the interproximal surface of the tooth at the correct height for placement of a given attachment when the pointer element is a marker element. This mark is preferably off center near the interproximal, so that an attachment may be attached to a tooth without covering the mark, thus serving as a constant guide in placing the attachment at the correct height. This feature alleviates the need to use a gauge a second time to check attachment position before the attachment is fixed in position. Where the pointer element is just used for measurement, the place where the tip of the pointer element rests on the tooth can be used to adjust the position of the brackets placed on the tooth.  
         [0028]    The gauge of the invention preferably also has a continuous range of settings to adjust the distance between axis A of longitudinal extension  36  and tip  50  pointer element  40 , since the gauge can have a general form of an arc drawing bow divider, with adjustment knurl and screws  46  serving this function (as shown in FIG. 3). In contrast, currently used gauges have three to four measurement heights that are fixed and not adjustable. Furthermore, these current gauges use the cusp tips of the posterior teeth rather than the marginal ridges as reference measuring points and have no marking capability. An added refinement to the gauge is to make the marking member able to slide forward and backward so that the gauge is first positioned on the tooth to be measured and the marker slides forward to place the mark on the tooth at the correct place.  
         [0029]    The dual axis principal of the gauge could also be used in gauges designed to measure correct placement heights for attachments that are fitted to models of a given patient&#39;s teeth for indirect placement of attachments on teeth. In this indirect mode, models are made of the teeth of a given patient and attachments are placed ideally on the models versus on the teeth of the patient. Through an impression made of the model with attachments placed thereon, the attachments can then be transferred in this impression to the actual teeth of the patient and permanently attached, for example, a quadrant of the mouth at a time. Such a method might be used for rapid attachment of the brackets to the patient&#39;s teeth.  
         [0030]    Having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the instant invention as set forth hereinabove and as described hereinbelow by the claims.