Patent Publication Number: US-2017367803-A1

Title: Dental measuring abutment and assembly

Description:
RELATED APPLICATION/S 
     This application claims the benefit of priority under 35 USC §119(e) of U.S. Provisional Patent Application No. 62/096,868 filed 25 Dec. 2014, the contents of which are incorporated herein by reference in their entirety. 
    
    
     FIELD AND BACKGROUND OF THE INVENTION 
     The present invention, in some embodiments thereof, relates to measuring parameters of a dental abutment, and more particularly, but not exclusively, to a dental measuring assembly configured for measuring a height and/or angle of a dental abutment. 
     US Publication number U.S. Pat. No. 8,651,865 B2 discloses “A set of one-piece angled abutments, each abutment including an angled stump, a short intermediate cylindrical portion, and a lower threaded portion, wherein the placement of the starting point of the thread within the first round in the lower threaded portion of each abutment determines the angular orientation from 0° to 360° attained by the stump once the abutment is fully tightened to an implant located in the patient&#39;s mandible, the set has a variable number of abutments depending on the value of the constant angular offset chosen for spacing the beginning of the thread of each abutment included in the set, each set being defined by a constant angular offset with a value which is a divisor of 360 and the sets of abutments being accompanied by a circular box to easily select the abutment that attains the ideal angular orientation for a patient&#39;s needs.” 
     The present invention, in some embodiments thereof, relates to dental implants. More specifically, the present invention, in some embodiments thereof, relates to a dental measuring abutment. 
     SUMMARY OF THE INVENTION 
     According to an aspect of some embodiments there is provided a dental measuring assembly comprising: an elongated stem defining a longitudinal axis between a proximal end and a distal end of the stem; a measuring abutment configured to be received over the proximal end of the stem and to axially slide over the stem; wherein a distal segment of the stem comprises scale markings denoting a height of a distal end of the measuring abutment relative to the stem. In some embodiments, the abutment is configured to closely-fit the stem such that wobbling of a long axis of the abutment relative to the longitudinal axis of the stem is smaller than 0.5°. In some embodiments, the distal segment of the shaft comprising the scale is formed with at least one of protrusions and indentations. In some embodiments, the stem is at least 10 mm long. In some embodiments, the stem is no more than 30 mm long. In some embodiments, the abutment comprises a distal annular portion defining a longitudinal bore in which the stem is received, the bore comprising a cross section profile corresponding with a cross section profile of the stem. In some embodiments, the cross section profiles are circular and a diameter of the longitudinal bore of the abutment is no more than 2% larger than a diameter of the stem. In some embodiments, a proximally extending portion of the measuring abutment comprises at least one inclined surface, the surface disposed at an angle relative to the longitudinal axis of the stem when the abutment is positioned over the stem. In some embodiments, the stem comprises a radially-outward extending shoulder configured on a distal end of the distal segment, the shoulder sized to limit sliding of the measuring abutment in a distal direction. In some embodiments, the abutment is held to the stem by a friction-fit coupling. In some embodiments, the friction is between two materials, and at least one of an outer surface of the stem and an inner surface of the abutment at the bore comprises a material having a high friction coefficient. In some embodiments, the outer surface of the stem comprises titanium and the inner surface of the abutment comprises rubber. In some embodiments, the distal annular portion of the abutment comprises a groove, and an elastic element is seated within the groove to tighten a fit of the abutment onto the stem. 
     In some embodiments, the distal annular portion of the abutment comprises a groove extending from an outer surface of the portion to an inner surface of the portion. 
     In some embodiments, a portion of the stem configured distally to the segment comprising the scale is configured to engage a dental implant. In some embodiments, the stem is attached to the dental implant by an interference-fit coupling. In some embodiments, the stem comprises distal extensions configured to press-fit into a cavity configured at a proximal portion of the implant, the distal extensions configured to spring radially outwardly to resist pull-out of the stem from the implant. In some embodiments, the distal extensions are shaped to resist rotation of the stem around an axis of the implant when the stem is attached to the implant. In some embodiments, a coupling between the implant and stem is configured to resist pull out force. In some embodiments, the inclined surface of the abutment is disposed at an angle between 0-90 degrees relative to the longitudinal axis of the stem. In some embodiments, the scale marks on the stem are denoted at non-equal intervals. 
     According to an aspect of some embodiments there is provided a dental measuring assembly kit comprising: an elongated stem defining a longitudinal axis between a proximal end and a distal end of the stem; a plurality of measuring abutments, each measuring abutment configured to be received over the proximal end of the stem and to axially slide over the stem; wherein a distal segment of the stem comprises scale markings denoting a height of a distal end of the measuring abutment relative to the stem; and wherein each measuring abutment comprises an inclined surface disposed at a different angle relative to the longitudinal axis of the stem. In some embodiments, the kit comprises at least three abutments: a first abutment defining an angle of 0 degrees relative to the longitudinal axis of the stem; a second abutment defining an angle of 15 degrees relative to the longitudinal axis of the stem; and a third abutment defining an angle of 25 degrees relative to the longitudinal axis of the stem. 
     According to an aspect of some embodiments there is provided a method of determining at least one of a height and angle of a dental abutment, comprising: positioning an elongated stem over a dental implant implanted in a jawbone of a patient; threading a measuring abutment over the stem; sliding the abutment axially on the stem to determine a height for a fixed abutment, the height being determined according to scale marks denoted on the stem; assessing whether an angle defined by the measuring abutment relative to the stem at the current layout is configured to fulfill functional requirements of a fixed abutment selected according to the current angle. In some embodiments, the method further comprises, following the assessing, replacing the measuring abutment with another measuring abutment defining a different angle relative to the longitudinal axis of the stem and repeating the assessing. In some embodiments, positioning the stem over the dental implant comprises press-fitting the stem into the implant. In some embodiments, positioning the measuring abutment over the stem comprises threading an annular portion of the abutment over a proximal end of the stem. 
     According to an aspect of some embodiments there is provided a stem for a measuring abutment for a dental implant, comprising: an elongated cylindrical shaft, the shaft being at least 10 mm long, the shaft comprising a distal portion configured to engage an implant in a jawbone, an intermediate portion sized to allow for a measuring abutment to move over it when placed on the stem; and a proximal portion. In some embodiments, the distal portion comprises one or more extensions configured to interference-fit within a head of the implant. In some embodiments, the intermediate portion comprises scale marks denoting a height of the abutment when placed over the stem. In some embodiments, the stem comprises a radially outward extending shoulder configured between the intermediate portion and the distal portion for limiting movement of the abutment on the stem in a distal direction when the abutment is positioned over the stem. 
     There is thus provided, in accordance with some embodiments of the present invention, a measuring abutment assembly for use with a dental implant, comprising an abutment stem arranged along a longitudinal axis, and a measuring abutment arranged at an angle with respect to the longitudinal axis. In some embodiments, the measuring abutment is slidably movable relative to the abutment stem. 
     In some embodiments, the measuring abutment is configured for friction-fit engagement with the abutment stem. In some embodiments, the measuring abutment assembly is in a friction-fit engagement with the dental implant. 
     In accordance with some embodiments of the present invention, the friction-fit engagement between the measuring abutment assembly and the dental implant is tighter than the friction-fit engagement between the measuring abutment and the abutment stem. 
     In accordance with some embodiments of the present invention, the measuring abutment includes a surface disposed at an angle with respect to the longitudinal axis. Optionally, the surface is disposed at an angle with respect to the longitudinal axis of the abutment stem. In some embodiments, the measuring abutment is arranged at an angle of 0° with respect to the longitudinal axis. 
     Alternatively, the surface is disposed at an angle of 15° with respect to the longitudinal axis. 
     Yet alternatively, the surface is disposed at an angle of 25° with respect to the longitudinal axis. 
     Alternatively, the surface is disposed at angle between 0-90 degrees, such as 20 degrees, 50 degrees, 70 degrees or intermediate, larger or smaller angles. 
     In accordance with some embodiments of the present invention the measuring abutment includes a plurality of surfaces disposed at different angles with respect to the longitudinal axis. 
     According to some embodiments of the invention, there is provided a measuring abutment assembly for use with a dental implant, comprising: an abutment stem arranged along a longitudinal axis; a measuring abutment arranged at an angle with respect to the longitudinal axis and wherein the measuring abutment is slidably movable relative the abutment stem. In some embodiments, the measuring abutment is in a friction-fit engagement with the abutment stem. In some embodiments, the measuring abutment assembly is in a friction-fit engagement with the dental implant. In some embodiments, the friction-fit engagement between the measuring abutment assembly and the dental implant is tighter than the friction-fit engagement between measuring abutment and abutment stem. In some embodiments, the measuring abutment includes a surface disposed at an angle with respect to the longitudinal axis. In some embodiments, the measuring abutment is arranged at an angle of 0° with respect to the longitudinal axis. Alternatively, the surface is disposed at an angle of 15° with respect to the longitudinal axis. Alternatively, the surface is disposed at an angle of 25° with respect to the longitudinal axis. In some embodiments, the measuring abutment includes a plurality of surfaces disposed at different angles with respect to the longitudinal axis. 
     Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced. 
       In the drawings: 
       The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which like components are denoted by like reference numerals: 
         FIG. 1A  is a simplified isometric view of a first angle measuring abutment, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 1B  is a simplified isometric view of a second angle measuring abutment, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 1C  is a simplified isometric view of a third angle measuring abutment, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 1D  is a flowchart of a method of selecting a fixed abutment using a measuring assembly, in accordance with some embodiments of the present invention; 
         FIG. 1E  is an illustration of a measuring assembly comprising a measuring abutment and an abutment stem mounted onto a dental implant in a jaw bone, according to some embodiments of the invention; 
         FIG. 2  is a simplified isometric view of an abutment stem, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 3A  is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 2  and the measuring abutment of  FIG. 1C , in accordance with some embodiments of the present invention; 
         FIG. 3B  is a simplified assembled view of a measuring assembly of  FIG. 3A , in accordance with some embodiments of the present invention; 
         FIG. 3C  is a simplified cross-sectional view of a measuring assembly of  FIG. 3B , section being taken along lines A-A in  FIG. 3B , in accordance with some embodiments of the present invention; 
         FIG. 4A  is a simplified assembled view of a measuring assembly of  FIG. 3B  assembled on an implant, in accordance with some embodiments of the present invention; 
         FIG. 4B  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 4A , section being taken along lines B-B in  FIG. 4A , in accordance with some embodiments of the present invention; 
         FIG. 5A  is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 2  and the measuring abutment of  FIG. 1A , in accordance with some embodiments of the present invention; 
         FIG. 5B  is a simplified assembled view of a measuring assembly of  FIG. 5A , in accordance with some embodiments of the present invention; 
         FIG. 5C  is a simplified cross-sectional view of a measuring abutment of  FIG. 5B , section being taken along lines C-C in  FIG. 5B ; 
         FIG. 6A  is a simplified assembled view of a measuring assembly of  FIG. 5B  assembled on an implant, in accordance with some embodiments of the present invention; 
         FIG. 6B  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 6A , section being taken along lines D-D in  FIG. 6A , in accordance with some embodiments of the present invention; 
         FIG. 7A  is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 2  and the measuring abutment of  FIG. 1B , in accordance with some embodiments of the present invention; 
         FIG. 7B  is a simplified assembled view of a measuring assembly of  FIG. 7A , in accordance with some embodiments of the present invention; 
         FIG. 7C  is a simplified cross-sectional view of a measuring assembly of  FIG. 7B , section being taken along lines E-E in  FIG. 7B , in accordance with some embodiments of the present invention; 
         FIG. 8A  is a simplified assembled view of a measuring assembly of  FIG. 7B  assembled on an implant, in accordance with some embodiments of the present invention; 
         FIG. 8B  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 8A , section being taken along lines F-F in  FIG. 8A , in accordance with some embodiments of the present invention; 
         FIG. 9  is a simplified illustration of a jaw bone with an implant and a measuring assembly assembled thereon, in accordance with some embodiments of the present invention; 
         FIG. 10  is an illustration of a measuring assembly comprising a measuring abutment and an abutment stem mounted onto a dental implant in a jaw bone, the assembly comprising an elastic element positioned at an interface between the stem and the abutment, according to some embodiments of the invention; 
         FIG. 11A  is a simplified isometric view of a first angle measuring abutment for use with an elastic element, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 11B  is a simplified isometric view of a second angle measuring abutment for use with an elastic element, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 11C  is a simplified isometric view of a third angle measuring abutment for use with an elastic element, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 12  is a simplified isometric view of an abutment stem for use with an elastic element, constructed and operative in accordance with some embodiments of the present invention; 
         FIG. 13A  is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 12  and the measuring abutment of  FIG. 12C , in accordance with some embodiments of the present invention; 
         FIG. 13B  is a simplified assembled view of a measuring assembly of  FIG. 13A , in accordance with some embodiments of the present invention; 
         FIG. 13C  is a simplified cross-sectional view of a measuring assembly of  FIG. 13B , section being taken along lines A-A in  FIG. 13B , in accordance with some embodiments of the present invention; 
         FIG. 14A  is a simplified assembled view of a measuring assembly of  FIG. 13B  assembled on an implant, in accordance with some embodiments of the present invention; 
         FIG. 14B  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 14A , section being taken along lines B-B in  FIG. 14A , in accordance with some embodiments of the present invention; 
         FIG. 14C  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 14A , cross section being transverse to the cross section shown in  FIG. 14B ; 
         FIG. 15A  is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 12  and the measuring abutment of  FIG. 11A , in accordance with some embodiments of the present invention; 
         FIG. 15B  is a simplified assembled view of a measuring assembly of  FIG. 15A , in accordance with some embodiments of the present invention; 
         FIG. 15C  is a simplified cross-sectional view of a measuring abutment of  FIG. 15B , section being taken along lines C-C in  FIG. 15B ; 
         FIG. 16A  is a simplified assembled view of a measuring assembly of  FIG. 15B  assembled on an implant, in accordance with some embodiments of the present invention; 
         FIG. 16B  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 16A , section being taken along lines D-D in  FIG. 16A , in accordance with some embodiments of the present invention; 
         FIG. 16C  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 16A , cross section being transverse to the cross section shown in  FIG. 16B ; 
         FIG. 17A  is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 12  and the measuring abutment of  FIG. 11B , in accordance with some embodiments of the present invention; 
         FIG. 17B  is a simplified assembled view of a measuring assembly of  FIG. 17A , in accordance with some embodiments of the present invention; 
         FIG. 17C  is a simplified cross-sectional view of a measuring assembly of  FIG. 17B , section being taken along lines E-E in  FIG. 17B , in accordance with some embodiments of the present invention; 
         FIG. 18A  is a simplified assembled view of a measuring assembly of  FIG. 17B  assembled on an implant, in accordance with some embodiments of the present invention; 
         FIG. 18B  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 18A , section being taken along lines F-F in  FIG. 18A , in accordance with some embodiments of the present invention; and 
         FIG. 18C  is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 18A , cross section being transverse to the cross section shown in  FIG. 18B . 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION 
     The present invention, in some embodiments thereof, relates to measuring parameters of a dental abutment, and more particularly, but not exclusively, to a dental measuring assembly configured for measuring a height and/or determining an angle of a dental abutment. 
     An aspect of some embodiments relates to determining parameters of a dental abutment that is to be implanted in a patient&#39;s mouth. In some embodiments, the parameters comprise a height of the abutment, determined for example according to a thickness of the gingiva. In some embodiments, the parameters comprise an angle of the abutment, determined for example according to an inclination of adjacent teeth and/or according to a dental occlusion anatomy of the patient. In some embodiments, parameters of the abutment are determined such that a dental prosthesis (e.g. crown or bridge) that is placed over the abutment will match a contour of the teeth. In some cases, the dental implant is positioned at an offset angle relative to a desired angle of the dental prosthesis (i.e. an angle that will aesthetically match the contour of the teeth), and the abutment is selected to compensate for the angle difference. 
     An aspect of some embodiments relates to a dental measuring assembly configured for determining a height and/or angle for a fixed abutment. In some embodiments, the dental measuring assembly comprises an elongated stem and an abutment configured to be positioned (e.g. threaded) over the stem. In some embodiments, a plurality of abutments are provided, each defining a different angle relative to the stem. Optionally, the abutments are positioned over the stem one at a time until an abutment that defines a best-fitting angle is selected. In some embodiments, the angle is defined between at least one inclined surface of the abutment, and the longitudinal axis of the stem. Optionally, the angle is determined so that the abutment, at the selected layout, will be positioned so that a crown, bridge or other prosthesis positioned on the abutment will fulfill one or more functional requirements such as matching a contour of the teeth, providing for jaw closure, and/or other requirements. 
     In some embodiments, the stem is configured to engage a dental implant. Optionally, the stem is positioned over the implant such that a longitudinal axis of the stem is directly aligned with a longitudinal axis of the implant, so that an angle measured between the abutment and stem is equivalent to an angle between the abutment and the implant. 
     An aspect of some embodiments relates to a dental measuring assembly in which the abutment is slidable over the stem. In some embodiments, the abutment is movable in a proximal and/or distal directions along the stem. In some embodiments, the stem comprises scale marks denoting a current height of the abutment, for example a current height of a distal end of the abutment relative to, for example, the gingival margin and/or the gingival-jawbone margin, when the stem is placed over an implanted dental implant. 
     In some embodiments, the measuring abutment snugly-fits the stem. Optionally, the abutment closely-fits the stem such that wobbling of the abutment relative to the stem is reduced or prevented. In some embodiments, wobbling of the abutment relative to the stem, for example between the long axis of the abutment and the long axis of the stem, is less than 0.5°, less than 1°, less than 2° or intermediate, larger or smaller angles. 
     In some embodiments, the abutment comprises an annular portion, defining a bore shaped and sized to receive the stem. In some embodiments, the annular portion is configured to be held onto the stem by a friction-fit coupling. In some embodiments, the annular portion of the abutment and the stem segment on which the abutment is movable comprise corresponding cross section profiles, for example both profiles are circular, or in another example the annular portion comprises an inner hexagonal profile and the stem comprises a circular profile. In some embodiments, in the example of corresponding circular cross section profiles, a tolerance of an inner diameter of the annular portion of the abutment and an outer diameter of the stem is selected to be restrictive enough so as to maintain the abutment held onto the stem, yet permissive enough to provide for relative sliding of the abutment on the stem. Additionally or alternatively, materials of at least the inner surface of the abutment and an outer surface of the stem are selected with a friction coefficient high enough to hold the abutment on the stem. In an example, the stem comprises titanium and the inner surface of the abutment comprises rubber. Additionally or alternatively, a fastening element such as an elastic element, for example a rubber band, is positioned at an interface between the abutment and stem, to tighten the coupling between them. In some embodiments, the elastic element is configured to compress the abutment over the stem. Optionally, the elastic element is seated in a groove formed in the annular portion of the abutment. Optionally, the groove comprises one or more openings through which the stem is exposed, allowing for direct contact between the elastic element, when seated in the groove, and the stem. 
     In some embodiments, the annular portion of the abutment is shaped to restrict movement other than axial movement of the abutment along the length of the stem. Optionally, to facilitate threading and/or sliding of the abutment over the stem, a groove is formed between the inner and outer surfaces of the annular portion. 
     In some embodiments, the stem comprises one more protrusions for limiting movement of the annular portion of the abutment over the stem. In an example, a distal portion of the stem comprises a radially outward extending shoulder limiting movement of the abutment in the distal direction. In another example, the scale on the stem is formed with protrusions and/or indentations. Optionally, the protrusions and/or indentations are sized to temporarily stop the abutment from sliding on the stem. Optionally, the groove formed in the annular portion of the abutment facilitates pushing the abutment over the protrusions and/or indentations of the scale, for example when measuring the height. 
     In some embodiments, a plurality of stems are provided, wherein in each stem the radially outward extending shoulder defines a different “zero height” level relative to the other stems. Optionally, the stem is selected according to its “zero height” level. Additionally or alternatively, a spacer (for example in the form of a ring) is placed over the stem to re-define the height reference level. Additionally or alternatively, as the angle depends on the height reference level, different height-angle combinations are tested. An aspect of some embodiments relates to a stem configured to engage a dental implant by an interference fit coupling. In some embodiments, a coupling between the stem and the implant is configured to resist, at least to some extent, pull-out of the stem from the implant. In some embodiments, the coupling is configured to resist rotation of the stem around the axis of the implant. Alternatively, the coupling permits rotation of the stem around the axis of the implant. 
     In some embodiments, a distal portion of the abutment comprises one or more extensions, for example distally extending fingers, configured to be received within a cavity of the implant to produce the interference-fit. Optionally, the extensions are configured to spring-outwardly with respect to the stem and to snap-fit into the implant cavity. Optionally, at least a portion of the extensions such as a distal portion is shaped to be received within respective recesses formed in the implant cavity, such as to prevent rotation of the stem relative to the long axis of the implant. In some embodiments, the extensions are pushed inwardly to allow removal of the stem from the implant. 
     According to an embodiment of the present invention, a measuring abutment is provided configured for measuring both angle and height of required prosthesis. 
     A dental prosthesis such as a crown, a bridge or any other dental prosthesis is to be fixedly fitted on a dental abutment that is manufactured using the measuring abutment that is described in detail hereinbelow. 
     In some embodiments, the stem comprises a longitudinal axis extending between a proximal end of the stem and a distal end of the stem; 
     In some embodiments, the abutment comprises a longitudinal axis passing through a respective center of the bore defined by the annular portion, and extending between the proximal end of the abutment and the distal end of the abutment; 
     In some embodiments, the implant comprises a longitudinal axis, extending between a proximal end of the implant and a distal end of the implant. 
     In some embodiments, two or more of the above mentioned axis are aligned with respect to each other, for example when the stem is placed over the implant such that its longitudinal axis is aligned directly above the implant axis. 
     A “fixed abutment”, as referred to herein, may include an abutment other than the measuring abutment that is to be placed in the patient&#39;s mouth. It is noted that the term “fixed”, as referred to herein, is used to distinguish between the measuring abutment, which is placed in the mouth for a short period of time (e.g. minutes), and an abutment that is to remain in the patient&#39;s mouth for a longer period of time. A “fixed abutment” may include a temporary abutment as well. The fixed abutment may include a custom made abutment, a prefabricated abutment, and/or any other type of connector between a dental implant and a prosthesis such as a crown or a bridge. In some embodiments, the fixed abutment is configured to engage a dental implant. Optionally, a coupling between the fixed abutment and the dental implant is strong enough to resist forces acting on the dental prosthesis that is positioned over the abutment, such as forces acting on the prosthesis during jaw movement (e.g. during chewing). 
     Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. 
     Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. 
     Referring to the figures,  FIG. 1D  is a flowchart of a method for selecting a fixed abutment using a measuring assembly, according to some embodiments of the invention. 
     In some embodiments, a decision is made (for example by a dentist or other clinical personnel) to implant an abutment ( 10 ). Optionally, the abutment is to be attached over an implant placed in the patient&#39;s jawbone, to support a crown, bridge and/or other dental prosthesis fixed onto the abutment. In some cases, it is desirable that the fixed abutment will provide for positioning a dental prosthesis such as a crown or bridge that will match the contour of the teeth. 
     In some cases, an angle for the fixed abutment is assessed. Optionally, the measured angle is an angle of an inclined surface of the abutment (for example as further discussed below) with respect to a longitudinal axis of the implant. In some embodiments, a height for the fixed abutment is assessed. Optionally, the height comprises a gingival thickness. In some embodiments, a width (e.g. diameter) of the abutment is assessed. In some embodiments, a length of the abutment and/or any other dimensions are assessed for selecting and/or fabricating a fixed abutment. 
     In some embodiments, a measuring assembly comprising a stem and an abutment positionable over the stem is provided for determining one or more of the abutment parameters referred to herein ( 11 ). Optionally, the abutment comprises at least one inclined surface, which, when the abutment is positioned over the stem, is disposed at an angle relative to a longitudinal axis of the stem. Optionally, the angle is between, for example, 0-25 degrees, 10-50 degrees, 35-85 degrees, such as 5 degrees, 15 degrees, 20 degrees, 30 degrees, 65 degrees, 70 degrees or intermediate, larger or smaller angles. 
     In some embodiments, the measuring assembly is positioned on a dental implant previously implanted in the jawbone of the patient ( 12 ). In some embodiments, the stem is configured to be attached to the implant. Optionally, at least a distal portion of the stem is shaped to engage the implant, for example by an interference-fit. In an example, the stem comprises distally extending resilient fingers that are received within a proximal receiving cavity of the implant, for example as further discussed herein. In some embodiments, the stem is compressively fitted over the implant. Optionally, a tight fit between the stem and the implant is obtained by selection of materials which increase the friction and/or reduce resiliency between the stem and the implant, for example both the stem and the implant comprise titanium and/or any other metal-metal interface. Additionally or alternatively, a tight fit between the stem and the implant is obtained by a defining a restrictive tolerance between the components. 
     In some embodiments, the abutment is placed over the stem ( 13 ), for example threaded over the stem. In some embodiments, at least a portion of the abutment which is threaded around the stem is shaped and/or sized to closely fit the stem. Optionally, the abutment substantially does not sway sideways relative to the stem. 
     In some embodiments, the abutment is held to the stem by a friction-fit coupling. Optionally, friction forces between the abutment and stem are high enough to prevent the abutment from easily sliding off of the stem, yet low enough to allow for sliding the abutment over at least a longitudinal segment of the stem. In some embodiments, the friction fit coupling between the stem and the abutment is obtained by selection of materials which increase the friction between the stem and the abutment, for example the stem comprises the titanium and at least an inner surface of the abutment, for example at the annular portion of the abutment which surrounds the stem, comprises rubber. Additionally or alternatively, a friction fit between the stem and the abutment is obtained by defining restrictive tolerance between the components. Additionally or alternatively, one or more structural elements of the stem and/or of the abutment are configured for interference fit. Additionally or alternatively, the abutment is held onto the stem with the aid of an elastic element and/or any other restricting element positioned at an interface between the abutment and stem. 
     In some embodiments, a structure of the abutment is designed to provide for relative sliding of the abutment over the stem, for example when determining a height for the fixed abutment. In some embodiments, the abutment is formed with one or more resilience-increasing elements, such as a groove extending from an outer surface of the abutment to an inner surface of the abutment. Optionally, the groove widens when the abutment is placed and/or moved on the stem, allowing for slight movement of opposing abutment portions relative to each other. 
     In some embodiments, a coupling between the stem and the implant is configured to withstand disengaging forces (such as axial pull-out force, torque and/or other forces applied to the stem). Optionally, the stem-implant coupling is stronger than the stem-abutment coupling. Such configuration may provide for moving the abutment over the stem (e.g. sliding) while movement of the stem relative to the implant is reduced or prevented. In some embodiments, a tighter fit between the implant and the stem is obtained by a smaller tolerance between these components, as compared to tolerances defined between the stem and the abutment. Additionally or alternatively, a tighter fit is obtained by selecting materials of higher friction at the stem-implant interface than at the stem-abutment interface. 
     In some embodiments, if the angle of a currently-used measuring abutment does not fit, (for example does not match the contour of adjacent teeth, and/or interferes with dental occlusion) the abutment is removed from the stem and replaced by an abutment that defines a different angle, larger or smaller, relative to the longitudinal axis of the stem. Optionally, a plurality of abutments are tested until a best-fitting angle is identified ( 14 ). 
     In some embodiments, the abutment is moved over the stem, for example slid over the stem in proximal and/or distal directions, to determine a height for the fixed abutment ( 15 ). Optionally, the height comprises gingival thickness. In some embodiments, the height is determined by sliding the abutment in a proximal direction (i.e. away from the implant) to expose a stem segment that extends across the gingiva. Optionally, scale marks denoted on the stem are referred to when assessing the abutment height. 
     Optionally, a model of a bridge and/or a crown are temporarily placed on the measuring abutment to imitate the fixed abutment and determine fit. 
     In some embodiments, a fixed abutment is selected according to the abutment parameters that were determined using the assembly, such as a height and/or angle of the abutment ( 16 ). Optionally, a prefabricated abutment is selected. Alternatively, an abutment is manufactured according to the determined parameters. In some embodiments, a length of a distal base portion of the fixed abutment is selected and/or fabricated to match the measured height. In some embodiments, an inclined surface of the fixed abutment is selected to match the measured angle. In some cases, if there is a slight mismatch between the selected angle and the actual angle of the fixed abutment, when placed in the mouth, the dentist may smooth out (e.g. by polishing) the inclined surface of the fixed abutment until a desired angle is reached. 
       FIG. 1E  illustrates a measuring assembly comprising a measuring abutment and an abutment stem mounted over a dental implant in a jaw bone, according to some embodiments of the invention. 
     In some embodiments, a measuring assembly comprising an abutment  20  and a stem  21  is temporarily attached to an implant  22  implanted in a jawbone  23  of a patient. 
     In some embodiments, stem  21  is coupled to implant  22  such that a longitudinal axis  24  of stem  21  is aligned with a longitudinal axis  25  of the implant. Alternatively, the stem is positioned at an angle relative to the implant. 
     In some embodiments, abutment  20  is placed over stem  21 . Optionally, abutment  20  comprises a distal annular portion  26  defining a bore that allows for threading the abutment over the stem. Optionally, an inner surface of the annular portion contacts an outer surface of the stem. 
     In some embodiments, abutment  20  comprises at least one surface  27  defining a plane which lies at an angle  1  relative to axis  24  of the stem. Optionally, surface  27  extends from annular portion  26  to a proximal end of the abutment  28 . Optionally, angle φ is between 0-90 degrees, for example 5, 15, 20, 35, 40, 65, 80 degrees or intermediate, larger or smaller angle relative to axis  24 . 
     In some embodiments, abutment  20  is moved over stem  21 , for example by sliding it over the stem, to select a height for the fixed abutment. Optionally, an abutment height such as height  29  is a distance between a proximal gingival margin  30  and a distal gingival margin  32 , at an interface with jawbone  23 . In some embodiments, height  29  ranges between 0-10 mm, such as 2 mm, 5 mm, 7 mm or intermediate, longer or shorter distances. In some embodiments, when measuring the height, abutment  20  is moved in proximal direction, exposing a stem segment extending between the proximal end of the implant and a distal end of the abutment. In some embodiments, scale marks  31  are denoted on the stem for indicating a current height of the abutment, as it is moved over the stem. In an example, scales are marked at 2 mm intervals. In the exemplary configuration shown in this figure, abutment  20  is axially positioned over the stem at an initial base position, and can be moved in the proximal direction to expose the underlying stem segment when height measurement is performed. 
     In some embodiments, the stem segment comprising the scale is formed with protrusions and/or indentations. Optionally, the protrusions and/or indentations define steps for stopping the abutment at the different height levels. 
     In some embodiments, the scale marks are denoted at equal distance intervals, for example at 2 mm intervals as noted above. Alternatively, the scale marks are denoted at non-equal intervals. 
     Reference is now made to  FIG. 1A , which is a simplified isometric view of a first angle measuring abutment, constructed and operative in accordance with some embodiments of the present invention and to  FIG. 1B , which is a simplified isometric view of a second angle measuring abutment, constructed and operative in accordance with some embodiments of the present invention, and to  FIG. 1C , which is a simplified isometric view of a third angle measuring abutment, constructed and operative in accordance with some embodiments of the present invention. 
     A measuring abutment  100  of a first angle, for example an angle of approximately 15°, is seen in  FIG. 1A . The measuring abutment  100  is arranged about a longitudinal axis  101  and includes a distal generally annular portion  102  and a proximal portion  104 , which is inclined and has an inclined planar surface  106 . The inclined planar surface  106  is disposed at angle φ1, which, in this exemplary embodiment, is approximately 15° with respect to axis  101 . In some embodiments, proximal portion  104  and the distal portion  102  are integrally formed. Alternatively, the proximal portion and the distal portion define separate components that can be attached together to form the abutment. 
     In some embodiments, a longitudinal bore  108  is formed through the distal portion  102  and through a part of the proximal portion  104  and arranged along axis  101 . The bore  108  defines an inner surface  110 . In some embodiments, axis  101  passes through a respective center of annular portion  102 . 
     In some embodiments, a groove  112  is formed on the circumference of distal portion  102  and extends into bore  108 . Optionally, groove  112  extends from an outer surface of the annular portion to an inner surface of the annular portion. Optionally, radially outward force applied to the inner surface of the annular portion (such as by the stem when the abutment is positioned over it) may cause widening of groove  112 , allowing abutment portions configured across the groove to move slightly away from each other. A potential advantage of groove  112  may include increasing a resiliency of the abutment, facilitating threading the abutment over the stem and/or moving the abutment over the stem. Optionally, groove  112  widens only to an extent which maintains the abutment on the stem to prevent them from disengaging. In some embodiments, groove  112  facilitates sliding the abutment over protrusions formed in the shaft, for example protrusions defined at the scale markings. 
     In some embodiments, groove  112  extends from the internal surface in a radially outward direction, but does extend all the way through to the external surface. 
     A measuring abutment  120  of a second angle, preferably an angle of approximately 25°, is seen in  FIG. 1B , in accordance with some embodiments of the invention. In some embodiments, the measuring abutment  120  is arranged about a longitudinal axis  101  and includes a distal generally annular portion  122  and a proximal portion  124 , which is inclined and has an inclined planar surface  126 . The inclined planar surface  126  is disposed at angle  12 , which is approximately 25° with respect to axis  101 . In some embodiments, the proximal portion  124  and the distal portion  122  are preferably integrally formed. 
     In some embodiments, a longitudinal bore  128  is formed through the distal portion  122  and part of the proximal portion  124  and arranged along axis  101 . The bore  128  defines an inner surface  130 . 
     In some embodiments, a groove  132  is formed on the circumference of distal portion  122  and extends into bore  128 . 
     A measuring abutment  140  of a third angle, for example an angle of approximately 0°, is seen in  FIG. 1C . In some embodiments, the measuring abutment  140  is arranged about a longitudinal axis  101  and includes a distal generally annular portion  142  and a proximal generally cylindrical portion  144 . In some embodiments, the proximal portion  144  and the distal portion  142  are preferably integrally formed. 
     In some embodiments, a longitudinal bore  148  is formed entirely through the distal portion  142  and through the proximal portion  144  and arranged along axis  101 . The bore  148  defines an inner cylindrical surface  150 . In some embodiments, proximal portion  144  is comprises a window  145 . Optionally, window  145  is defined by a cut-out portion of the cylindrical abutment wall. Optionally, window  145  provides visual access to the stem when the abutment is positioned over the stem, allowing the dentist to determine the height. 
     In some embodiments, a groove  152  is formed on the circumference of distal portion  142  and extends into bore  148 . 
     Reference is now made to  FIG. 2 , which is a simplified isometric view of an abutment stem, constructed and operative in accordance with some embodiments of the present invention. 
     In some embodiments, an abutment stem  160  is an integrally made generally cylindrical part arranged longitudinally about axis  101 . Alternatively, abutment stem  160  is comprised of more than one part. 
     In some embodiments, the abutment stem  160  has a proximal cylindrical portion  162  having an outer surface  163 , an intermediate portion  164  having, according to some embodiments, an outer polygonal surface  166 , optionally a hexagonal outer surface, and a distal portion  168  composed of a plurality of relatively resilient fingers  170 , optionally forming a gap therebetween. Optionally, each of the fingers  170  has a relatively widened distal portion  172 . 
     In some embodiments, marking scales  174  are denoted on the circumference of proximal cylindrical portion  162  of abutment stem  160 . In some embodiments, for example as shown herein, the scale comprises protrusions and/or indentations formed relative to the stem shaft. A potential advantage of a height scale comprising protrusions and/or indentations may include providing sensible feedback to the dentist that the abutment was moved over to another scale mark. 
     In some embodiments, the intervals between the markings are of an equal distance. Alternatively, the intervals are set at non-equal distances. 
     In some embodiments, stem  160  comprises a radially outward extending shoulder  171 . Optionally, shoulder  171  acts as stopper for limiting movement of the abutment in a distal direction when the abutment is threaded over the stem. Optionally, different stems may be provided including shoulders positioned at different heights relative to the stem, redefining the “zero height” reference. Additionally or alternatively, a spacing element (for example an annular ring) may be positioned over the stem to set a different height reference level. 
     Reference is now made to  FIG. 3A , which is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 2  and the measuring abutment of  FIG. 1C  and to  FIG. 3B , which is a simplified assembled view of a measuring assembly of  FIG. 3A  and to  FIG. 3C , which is a simplified cross-sectional view of a measuring assembly of  FIG. 3B , section being taken along lines A-A in  FIG. 3B , in accordance with some embodiments of the invention. 
     In some embodiments, as shown for example in  FIGS. 3A-3C , measuring abutment  140  is assembled onto abutment stem  160  to form a first adjustable measuring assembly  180 . 
     In some embodiments, measuring abutment  140  is slidably movable along the proximal portion  162  of abutment stem  160 . In some embodiments, there is a friction fit between the inner surface  150  of measuring abutment  140  and the outer surface  163  of abutment stem  160 . In some embodiments, the groove  152  on the distal portion  142  of measuring abutment  140  provides for relative resiliency of the distal portion  142  and thus allows sliding movement of the measuring abutment  140  along abutment stem  160 . 
     In some embodiments, the proximal portion  162  of abutment stem  160  is inserted into measuring abutment  140  through bore  148 . In some embodiments, an inner diameter  149  of bore  148  is sized according to an outer diameter  151  of stem  160 . Optionally, a tolerance defined between the diameters is selected to maintain the abutment held to the stem, yet to provide for relative sliding of the abutment over the stem. In an example, diameter  149  of the abutment is no more than 2%, 5%, 25% or intermediate, higher or smaller percentages larger than diameter  151  of the stem. 
     In some embodiments, measuring abutment  140  and abutment stem  160  are arranged along a mutual longitudinal axis  101 . 
     In some embodiments, materials of an inner surface of bore  148  of the abutment and/or materials of at least an outer surface of portion  162  of the stem are selected according to their friction coefficient, for example to increase friction forces between the stem and the implant. In an example, the outer surface of the stem comprises metal, and the inner surface of the abutment comprises rubber. In another example, the inner surface of the abutment comprises plastic. 
     Reference is now made to  FIG. 4A , which is a simplified assembled view of a measuring assembly of  FIG. 3B  assembled on an implant and to  FIG. 4B , which is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 4A , section being taken along lines B-B in  FIG. 4A , in accordance with some embodiments. 
     In some embodiments, as shown for example in  FIGS. 4A &amp; 4B , adjustable measuring assembly  180  is assembled onto a dental implant  200 . 
     In some embodiments, the intermediate hexagonal portion  164  of abutment stem  160  is inserted into a corresponding hexagonal portion  202  of the dental implant. It is noted that the abutment stem may comprise a configuration other than hexagonal (for example circular, squared, and/o other configurations) shaped to be received in a recess which comprises a matching profile, configured at a proximal portion of the implant. 
     In some embodiments, abutment stem  160  comprises one or more distally extending elements configured to engage the implant. In some embodiments, the implant-engaging elements are in the form of distal fingers  170 . In some embodiments, the distal fingers  170  of abutment stem  160  are inserted into an internal cavity  204  of the dental implant  200 . In some embodiments, there is a friction fit between the surface of the internal cavity  204  of dental implant  200  and the widened section  172  of fingers  170  of abutment stem  160 . In some embodiments, distal fingers  170  are configured to spring outwardly in a radial direction. Optionally, fingers  170  push against the wall of internal cavity  204  of the dental implant, producing an interference fit between the implant and stem. Optionally, the fingers are shaped to snap-fit into respective recesses in the internal cavity of the implant. In some embodiments, a resiliency of the distal fingers is selected to provide a coupling of a certain strength. 
     In some embodiments, the dental implant  200  has a proximal end  206  and a distal end  208 . 
     In some embodiments, friction forces between the surface of the internal cavity  204  of dental implant  200  and the widened section  172  of fingers  170  of abutment stem  160  are higher than friction forces between the inner surface  150  of measuring abutment  140  and the outer surface  163  of abutment stem  160 , thus the measuring abutment  140  can be slidably moved along the abutment stem  160  without causing disattachment of the measuring assembly  180  from the dental implant  200 . Optionally, widened section  172  of the fingers is shaped to resist pull out of the stem from the implant. In some embodiments, the fingers are shaped to resist axial rotation of the stem when attached to the implant. 
     In some embodiments, to remove the stem form the implant, the distally extending fingers are forced radially inwardly relative to the walls of internal cavity  204  of the implant, enabling the stem to be moved away from the implant. 
     In some embodiments, positioning measuring assembly  140  on an abutment stem  160  and assembly of the adjustable measuring assembly  180  on the dental implant  200  provides for identification of the required abutment angle to be 0°. In some embodiments, the slidable movement of the measuring abutment  140  along the abutment stem  160  provides for identification of the required abutment height. Optionally, the required height is identified in accordance to the marking scale  174 , which is aligned with the distal portion  142  of the measuring abutment  140  once the adjustable measuring assembly  180  is assembled onto the implant  200  and assumes a certain height relative to the jaw bone, this height is measured using relative movement between the measuring abutment  140  and the abutment stem  160 . 
     Reference is now made to  FIG. 5A , which is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 2  and the measuring abutment of  FIG. 1A  and to  FIG. 5B , which is a simplified assembled view of a measuring assembly of  FIG. 5A  and to  FIG. 5C , which is a simplified cross-sectional view of a measuring assembly of  FIG. 5B , section being taken along lines C-C in  FIG. 5B . 
     In some embodiments, as shown for example in  FIGS. 5A-5C , measuring abutment  100  is assembled onto abutment stem  160  to form a second adjustable measuring assembly  182 . 
     In some embodiments, measuring abutment  100  is slidably movable along the proximal portion  162  of abutment stem  160 . In some embodiments, there is a friction fit between the inner surface  110  of measuring abutment  100  and the outer surface  163  of abutment stem  160 . In some embodiments, the groove  112  on the distal portion  102  of measuring abutment  100  provides for relative resiliency of the distal portion  102  and thus allows slidable movement of the measuring abutment  100  along abutment stem  160 . 
     In some embodiments, the proximal portion  162  of abutment stem  160  is inserted into measuring abutment  100  through bore  108 . 
     In some embodiments, inclined surface  106  of measuring abutment  100  is disposed at an angle of, for example, 15° with respect to the longitudinal axis  101  about which abutment stem  160  extends. 
     Reference is now made to  FIG. 6A , which is a simplified assembled view of a measuring assembly of  FIG. 5B  assembled on an implant and to  FIG. 6B , which is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 6A , section being taken along lines D-D in  FIG. 6A . 
     In some embodiments, for example as shown in  FIGS. 6A &amp; 6B , the second adjustable measuring assembly  182  is assembled onto a dental implant  200 . 
     In some embodiments, the intermediate hexagonal portion  164  of abutment stem  160  is inserted into a corresponding hexagonal portion  202  of the dental implant. In some embodiments, the distal fingers  170  of abutment stem  160  are inserted into an internal cavity  204  of the dental implant  200 . In some embodiments, there is a friction fit between the surface of the internal cavity  204  of dental implant  200  and the widened section  172  of fingers  170  of abutment stem  160 . 
     It is noted that the dental implant  200  has a proximal end  206  and a distal end  208 . 
     In some embodiments, friction forces between the surface of the internal cavity  204  of dental implant  200  and the widened section  172  of fingers  170  of abutment stem  160  are higher than friction forces between the inner surface  110  of measuring abutment  100  and the outer surface  163  of abutment stem  160 , thus the measuring abutment  100  can be slidably moved along the abutment stem  160  without causing disattachment of the adjustable measuring assembly  182  from the dental implant  200 . 
     In some embodiments, positioning measuring abutment  100  on an abutment stem  160  and assembly of the adjustable measuring assembly  182  on the dental implant  200  provides for identification of the required abutment angle to be 15°. In some embodiments, the slidable movement of the measuring abutment  100  along the abutment stem  160  provides for identification of the required abutment height. Optionally, the required height is identified in accordance to the marking scale  174 , which is aligned with the distal portion  102  of the measuring abutment  100  once the measuring assembly  182  is assembled onto the implant  200  and assumes a certain height relative to the jaw bone. Optionally, this height is measured using relative movement between the measuring abutment  100  and the abutment stem  160 . 
     In some embodiments, inclined surface  106  can be alternatively disposed at any other angle with respect to longitudinal axis  101 . 
     Reference is now made to  FIG. 7A , which is a simplified exploded view of a measuring assembly, including the abutment stem of  FIG. 2  and the measuring abutment of  FIG. 1B  and to  FIG. 7B , which is a simplified assembled view of a measuring assembly of  FIG. 7A  and to  FIG. 7C , which is a simplified cross-sectional view of a measuring assembly of  FIG. 7B , section being taken along lines E-E in  FIG. 7B . 
     In some embodiments, as shown for example in  FIGS. 7A-7C , measuring abutment  120  is assembled onto abutment stem  160  to form a third adjustable measuring assembly  184 . 
     In some embodiments, measuring abutment  120  is slidably movable along the proximal portion  162  of abutment stem  160 . In some embodiments, there is a friction fit between the inner surface  130  of measuring abutment  120  and the outer surface  163  of abutment stem  160 . In some embodiments, the groove  132  on the distal portion  122  of measuring abutment  120  provides for relative resiliency of the distal portion  122  and thus allows slidable movement of the measuring abutment  120  along abutment stem  160 . 
     In some embodiments, the proximal portion  162  of abutment stem  160  is inserted into measuring abutment  120  through bore  128 . 
     In some embodiments, inclined surface  126  of measuring abutment  120  is disposed at an angle of preferably 25° with respect to the longitudinal axis  101  about which abutment stem  160  extends. 
     Reference is now made to  FIG. 8A , which is a simplified assembled view of a measuring assembly of  FIG. 7B  assembled on an implant and to  FIG. 8B , which is a simplified cross-sectional view of a measuring assembly assembled on an implant of  FIG. 8A , section being taken along lines F-F in  FIG. 8A . 
     In some embodiments, as shown for example in  FIGS. 8A &amp; 8B , third adjustable measuring assembly  184  is assembled onto a dental implant  200 . 
     In some embodiments, the intermediate hexagonal portion  164  of abutment stem  160  is inserted into a corresponding hexagonal portion  202  of the dental implant. In some embodiments, the distal fingers  170  of abutment stem  160  are inserted into an internal cavity  204  of the dental implant  200 . In some embodiments, there is a friction fit between the surface of the internal cavity  204  of dental implant  200  and the widened section  172  of fingers  170  of abutment stem  160 . 
     It is noted that the dental implant  200  has a proximal end  206  and a distal end  208 . 
     In some embodiments, friction forces between the surface of the internal cavity  204  of dental implant  200  and the widened section  172  of fingers  170  of abutment stem  160  are higher than friction forces between the inner surface  130  of measuring abutment  120  and the outer surface  163  of abutment stem  160 , thus the measuring abutment  120  can be slidably moved along the abutment stem  160  without causing disattachment of the measuring assembly  184  from the dental implant  200 . 
     In some embodiments, positioning measuring abutment  120  on an abutment stem  160  and assembly of the adjustable measuring assembly  184  on the dental implant  200  provides for identification of the required abutment angle to be 25°. The slidable movement of the measuring abutment  120  along the abutment stem  160  provides for identification of the required abutment height. In some embodiments, the required height is identified in accordance to the marking scale  174 , which is aligned with the distal portion  122  of the measuring abutment  120  once the adjustable measuring assembly  184  is assembled onto the implant  200  and assumes certain height relative to the jaw bone, this height is measured using relative movement between the measuring abutment  120  and the abutment stem  160 . 
     In some embodiments, the inclined surface  126  can be alternatively disposed at any other angle with respect to longitudinal axis  101 . 
     Reference is now made to  FIG. 9 , which is a simplified illustration of a jaw bone with an implant and a measuring abutment assembled thereon, according to some embodiments. 
     In some embodiments, as shown for example in  FIG. 9 , adjustable measuring assembly such as  180  or  182  or  184  is assembled on to dental implant  200  in order to identify the dimensions of a fixed abutment to be placed onto the dental implant  200  in order to fixate a dental prosthesis on the gingiva of a patient. 
     In some embodiments, a single measuring assembly provides for measuring both the required angle and height of fixed abutment relative to the jaw bone. 
     In some embodiments, each of measuring abutment  100 ,  120  or  140  may be assembled onto measuring stem  160  in order to measure both angle and height of the required fixed abutment. Alternatively all three measuring abutments, or any other number of measuring abutments, can be formed as a single integral part by creating several inclined surfaces on the measuring abutment, while each inclined surface is disposed at a different angle with respect to longitudinal axis  101  of the abutment stem  160 . In this alternative embodiment where several inclined surfaces are formed on a single measuring abutment, a single measuring assembly can replace an entire planning kit including a plurality of measuring abutments, as this single measuring assembly enables measuring the required height and several angles at once. 
       FIG. 10  is an illustration of a measuring assembly comprising a measuring abutment and an abutment stem mounted onto a dental implant in a jaw bone, the assembly comprising an elastic element positioned at an interface between the stem and the abutment, according to some embodiments of the invention. 
     In some embodiments, a coupling between the abutment  1000  and stem  1002  comprises an elastic element  1004 . Optionally, elastic element  1004  is positioned to elastically compress at least a portion of the abutment to tighten the fit between the abutment and the stem. In some embodiments, abutment  1000  comprises a groove  1006 , configured for example on a distal annular portion  1008 , for receiving the elastic element. In some embodiments, when elastic element is seated in the groove, it applies a radial pressure for maintaining a tight fit between the abutment and stem. Optionally, the elastic element is elastic enough to provide for sliding the abutment over the stem. In some embodiments, at least some portions of the groove are formed all the way through the abutment material, exposing the stem to allow direct contact between the elastic element and the stem. A potential advantage of placing an elastic element over the abutment at the abutment-stem interface may include compensating for tolerance differences, potentially allowing for a less restrictive abutment-stem tolerance yet still maintaining the abutment held to the stem and movable on the stem. 
     In some embodiments, the elastic element  1004  is a band. Optionally, the band is formed of rubber. Optionally, the band is elliptical and not annular so as to be seated in a non-annular groove  1006  of the abutment, being exposed to the stem along some open portions of the groove and overlying abutment portions along other portions of the groove. In an example, open portions of the groove are configured on opposing circumferential segments. 
     The description of the following  FIGS. 11-18 , according to some embodiments of the invention, corresponds to the above description of  FIGS. 1-8  (i.e.  FIG. 11A  corresponds to  FIG. 1A ,  FIG. 12  corresponds to  FIG. 2 , etc), apart from that the distal annular portion  1008  of the abutment comprises a groove  1006  in which an elastic element  1004  is seated.  FIGS. 14C, 16C and 18C  show a cross section view transverse to the one shown in  FIGS. 14B, 16B and 8B  respectively, showing the elastic element  1004  directly contacting the stem along some portions of the elastic element, through one or more openings defined in groove  1006  of the abutment, in accordance with some embodiments of the invention. 
     It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereof which are not in the prior art. 
     The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”. 
     The term “consisting of” means “including and limited to”. 
     The term “consisting essentially of” means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. 
     As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof. 
     Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. 
     Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. 
     As used herein the term “method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts. 
     As used herein, the term “treating” includes abrogating, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating clinical or aesthetical symptoms of a condition or substantially preventing the appearance of clinical or aesthetical symptoms of a condition. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements. 
     All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.