Patent Publication Number: US-2013236852-A1

Title: Universal dental implant structure

Description:
FIELD OF THE INVENTION 
     The present invention relates to a dental implant structure and particularly to a universal dental implant structure. 
     BACKGROUND OF THE INVENTION 
     The technology of dental implant is well developed now. Dental implant is performed first by implanting an implant made of titanium that has high bio-compatibility into an alveolus for positioning. After few months when the implant has been firmly fastened to the bone in the alveolus, a denture is mounted. As the implant is directly connected to the bone, a desired support force can be provided for chewing harder foods. Thus it is widely accepted. The conventional dental implant includes an implant member which can be categorized into a one-piece type and a multi-piece type. The one-piece type implant member, such as U.S. publication No. 2010/0119993 entitled “Dental implant” is to directly implant the one-piece type implant member into the cancellous bone and cortical bone of the gum. After few months when the one-piece type implant member is integrated and fastened to the cancellous bone and cortical bone, a tooth cap is molded and mounted onto the one-piece type implant member. Such a method has the advantage of less restriction on the implant depth, and the implant member is sturdier and less likely to be fractured. But it also has a drawback, i.e., as the one-piece type implant member is extended outside the cortical bone about 10 mm, occlusion interference easily takes place when chewing of the patient during the bone integration period. This could result in strength deficiency of the bone integration and affect the sturdiness after implantation, and the bone could be atrophied to result in implantation failure. Moreover, the one-piece type implant member cannot be coupled with other tooth cap, the design space and types of the denture also are limited. 
     The multi-piece type implant member, such as U.S. publication No. 2007/0254265 entitled “Dental implant” includes an implant member, an abutment and a crown. During implantation process, the implant member is implanted first in the cancellous bone and cortical bone of the gum without jutting outside the cortical bone. As the cortical bone is covered by a layer of soft tissue and the oral cavity is located right above the soft tissue, no occlusion interference occurs after the implant member is implanted. Once the implant member and the cancellous bone and cortical bone are integrated and fastened, the soft tissue is then incised via surgery and the abutment is fastened to the implant member for positioning; finally, the crown is molded and mounted onto the abutment jutting outside the soft tissue. Such an approach has the advantage of eliminating the occlusion interference and making diversified designs of the crown possible to mate different types of tooth caps; however, it also has a drawback, i.e. the implant member must be precisely fastened and leveled on the cortical bone to facilitate coupling of the crown in the later process. As uncertainty still cannot be totally eliminated in medical clinics, if the implant member is implanted too deep into the cortical bone, it will be slightly covered by the cortical bone during bone integration period to result in difficulty of coupling with the crown in the later process. Another drawback is having weaker structural strength. Since the crown is mostly fastened to the implant member by screwing and positioned in the soft tissue, its horizontal bracing force also is insufficient. Thus when the crown is subject to a horizontal shearing force, the screw fastening structure could be easily fractured. In the event that such an incident happens, the residual screw fastener still remains in the implant member to cause removing and repair difficult. To resolve the aforesaid issues, the implant member and the abutment in this prior art are coupled together to form an abutment joint, and the crown is coupled on the abutment joint, thereby can withstand a greater horizontal shearing force to avert transverse fracturing. 
     As the one-piece type implant member is extended outside the cortical bone about 10 mm after implantation, and two-piece type implant member is also extended outside the cortical bone about 10 mm after mounting the abutment, in the event that the occlusion space between the upper and lower teeth of a patient is smaller, either of the implant member of the one-piece type or abutment of the two-piece type has to be ground for a selected height to meet actual requirement. It is troublesome in use. Moreover, a dentist has to prepare one-piece implant structure and two-piece implant structure to meet requirements of different patients, and they cannot be interchanged. Thus usability is lower, and the costs also are higher. 
     Please refer to  FIGS. 1A and 1B , when the conventional dental implant is performed, as the gum  1  could be uneven to cause tilt or bump, when an implant member  2  of a two-piece dental implant structure is implanted into the gum  1 , the implant member  2  could be exposed outside the gum  1  to result in undesired appearance as shown in  FIG. 1A . Moreover, because the implant member  2  has multiple screw threads formed on the surface thereof, the exposed screw threads could breed microbes and cause ailments. To prevent exposure of the screw threads, additional fabrication processes are needed that are time-consuming and costly. Also referring to  FIG. 1B , if the implant member  2  is implanted too depth into the gum  1 , mounting of the abutment in the later process could be difficult. There is still room for improvement. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a universal dental implant structure adaptable to both one-piece type and two-piece type dental implants. 
     Another object of the invention is to solve the problem of the conventional dental implant structure that requires extra grinding process for inadequate occlusion space and is time-consuming and effort-wasting. 
     Yet another object of the invention is to overcome the problem of the conventional dental implant structure that is easily fractured caused by the horizontal shearing force. 
     To achieve the foregoing objects, the present invention provides a universal dental implant structure that is implanted and positioned on a patient&#39;s gum. The gum has a cancellous bone, a cortical bone located on the surface of the cancellous bone and a soft tissue located at one side of the cortical bone remote from the cancellous bone. The universal dental implant structure includes an implant member and a tooth cap. The implant member has an implant portion, an extended holding portion connecting to the implant portion and a coupling cavity located on one side of the extended holding portion remote from the implant portion. The coupling cavity is extended from the extended holding portion towards the implant portion and has an internal thread section on an inner surface thereof. The implant portion is anchored in the cancellous bone and cortical bone. The extended holding portion is extended outside the cortical bone in a range between 3 mm and 6 mm. The tooth cap has a coupling portion to couple on and fasten to the extended holding portion for positioning. 
     The structure thus formed provides features as follow: 
     1. With the extended holding portion extended outside the cortical bone between merely 3 mm and 6 mm the problem of occlusion interference during bone integration can be averted and inadequate bone integration strength can be prevented. 
     2. Compared with the conventional technique of extending the implant member outside the cortical bone about at least 10 mm, the invention extends the implant member by 3 mm to 6 mm, thus is avoided performing the grinding adjustment caused by inadequate occlusion space between the upper teeth and lower teeth and the problems of time-consuming and effort-wasting. 
     3. In the event that the occlusion space is insufficient, the tooth cap and implant member can be coupled to get the advantage of the one-piece dental implant structure. On the other hand, when the occlusion space is greater, an abutment can be used to fasten to the coupling cavity of the implant member to achieve the advantage of the two-piece dental implant structure with the flexibility of changing shape and size of the abutment. Thereby it is adaptable to one-piece type and two-piece type structure. 
     4. The dentist requires preparing merely the implant member with the same specification to meet the requirements of different patients, thus usability improves. 
     The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic view of a conventional dental implant on an uneven gum. 
         FIG. 1B  is another schematic view of a conventional dental implant on an uneven gum. 
         FIG. 2  is an exploded view of a first embodiment of the invention. 
         FIG. 3  is a schematic view of the invention showing a teeth occlusion space. 
         FIG. 4A  is a schematic view of the first embodiment showing positioning of the implant member. 
         FIG. 4B  is a schematic view of the first embodiment showing positioning of the tooth cap. 
         FIG. 5  is a schematic view of a second embodiment showing positioning of the tooth cap. 
         FIG. 6  is an exploded view of a third embodiment of the invention. 
         FIG. 7  is an exploded view of a fourth embodiment of the invention. 
         FIG. 8A  is a schematic view of the fourth embodiment of the invention showing positioning of the implant member. 
         FIG. 8B  is a schematic view of the fourth embodiment of the invention showing positioning of the abutment. 
         FIG. 8C  is a schematic view of the fourth embodiment of the invention showing positioning of the tooth cap. 
         FIG. 9  is a schematic view of a fifth embodiment of the invention showing positioning of the implant member in the gum. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 2 and 4A , the present invention aims to provide a universal dental implant structure implanted in a patient&#39;s gum  10 . The gum  10  has a cancellous bone  11 , a cortical bone  12  located on the surface of the cancellous bone  11  and a soft tissue  13  located at one side of the cortical bone  12  remote from the cancellous bone  11 . The universal dental implant structure includes an implant member  20  and a tooth cap  30 . The implant member  20  has an implant portion  21 , an extended holding portion  22  connecting to the implant portion  21  and a coupling cavity  23  located on one side of the extended holding portion  22  remote from the implant portion  21 . The coupling cavity  23  is extended from the extended holding portion  22  towards the implant portion  21  and has an internal thread section  231  on an inner surface thereof. The tooth cap  30  has a coupling portion  31  to encase and fasten to the extended holding portion  22 . 
     In the event that the dental implant is done on a lower tooth and a small occlusion space is formed between the upper tooth and lower tooth, referring to  FIG. 3 , if the upper tooth  70  and the lower soft tissue  13  are spaced from each other at a distance d 1  of merely 5 mm, a one-piece dental implant structure as previously discussed can be chosen. As the extended holding portion  22  is extended merely outside the cortical bone  12  in a range between 3 mm and 6 mm, the length of the extended holding portion  22  can be selected according to the soft tissue  13  and the occlusion space between the upper and lower teeth of the patient. For instance, assumed that the soft tissue  13  has a thickness d 2  of 2 mm, the length d 3  of the extended holding portion  22  extended outside the soft tissue  13  can be 1 mm to 4 mm so that there is still sufficient room for mounting the tooth cap  30  without a great deal of extra fabrication. 
     Also referring to  FIG. 4A , the implant portion  21  is anchored in the cancellous bone  11  and cortical bone  12 , and the extended holding portion  22  is extended outside the cortical bone  12  in a range between 3 mm and 6 mm and partly covered by the soft tissue  13 . The soft tissue  13  is formed at a thickness about 1 mm to 2 mm, depending on the patient. After the implant portion  21  has been anchored in the cancellous bone  11  and cortical bone  12 , a bone integration period is required. When this period is elapsed, referring to  FIG. 4B , the tooth cap  30  is coupled on the implant member  20 . Referring to  FIG. 5 , in order to reinforce coupling between the tooth cap  30  and implant member  20 , the tooth cap  30  further has an auxiliary holding portion  32  inserted into the coupling cavity  23  so that contact area between the tooth cap  30  and implant member  20  increases. The auxiliary holding portion  32  also can enhance the strength of the tooth cap  30  to withstand the horizontal shearing force. Furthermore, the gap between the auxiliary holding portion  32  and coupling cavity  23  is filled with adhesive  60  to form secure bonding. While the implant member  20  of the conventional technique includes merely the implant portion  21 , the length of the coupling cavity  23  is controlled via the length of the implant portion  21 . However, in the invention, as the coupling cavity  23  covers a greater range that includes the implant portion  21  and extended holding portion  22 , it has a greater length to increase the depth for coupling, thus more contact area is provided to improve coupling between them. 
     In the event that sufficient occlusion space is provided, after the implant member  20  is embedded, the two-piece dental implant structure can be selected to get more choices of the tooth cap  30 . Referring to  FIG. 6 , the invention can also provide an abutment  40  fastened to the implant member  20 . The abutment  40  has a fastening portion  41  fastened to the coupling cavity  23  and a holding portion  42  outside the coupling cavity  23  connected to the fastening portion  41 . The tooth cap  30  has a housing space that mates the shape of the holding portion  42  to hold the holding portion  42  so that the tooth cap  30  couples on the abutment  40  and fastens to the extended holding portion  22  via the coupling portion  31 , thereby after the implant member  20  is embedded, various types of the abutment  40  and tooth cap  30  can be selected for mating. It is to be noted that the tooth cap  30  fully covers the holding portion  42  and anchors on the extended holding portion  22 , hence can withstand greater horizontal shearing force. 
     Please refer to  FIG. 7  for another type of structure of the abutment  40   a . It has a holding portion  42   a  and a fastening hole  43  running through the holding portion  42   a . The fastening hole  43  is run through by a screw fastener  50  to fasten to the coupling cavity  23 , thereby is coupled the implant member  20  and the abutment  40   a  together. The tooth cap  30  has a housing space mating the shape of the holding portion  42   a  to hold the holding portion  42   a . The tooth cap  30  encases the abutment  40   a  and fastens to the extended holding portion  22  via the coupling portion  31 . Also referring to  FIG. 8A , implantation of the implant member  20  is the same as that of the one-piece type, by implanting the implant portion  21  in the cancellous bone  11  and cortical bone  12 , with the extended holding portion  22  formed on the soft tissue  13  and extended outside the cortical bone  12  by 3 mm to 6 mm. The implant portion  21  has an external thread section  211  on the outer surface thereof to fasten to the cortical bone  12  and cancellous bone  11  by screwing. 
     Referring to  FIG. 8B , after the bone integration has been finished, the abutment  40   a  is fastened to the implant member  20 . In this embodiment, the fastening hole  43  is run through by the screw fastener  50  to fasten to the coupling cavity  23  so that the abutment  40   a  is positioned on the implant member  20 . It is to be noted that the extended holding portion  22  of the implant member  20  is a recess located on one side remote from the implant portion  21  to facilitate fastening of the abutment  40   a  and also increase the structural strength of the abutment  40   a  in the horizontal direction. 
     Referring to  FIG. 8C , after the abutment  40   a  is fastened, the tooth cap  30  can be made by mating the tooth location via the holding portion  42   a  through molding. The tooth cap  30  can fully encase the abutment  40   a  by bonding via adhesive. By fastening the coupling portion  31  to the extended holding portion  22  a firmer holding effect can be accomplished. 
     Referring to  FIG. 9 , in the event that the gum  10  is tilted or bulged, the extended holding portion  22  can prevent the thread section  211  of the implant portion  21  from exposing, thus is avoided the problem of microbe infection and ailments. Such an approach can also prevent the implant member  20  from implanting too deep into the gum  10 , hence is avoided difficulty in the later treatment. 
     It also to be noted that the extended holding portion  22  can also serve as a buffer for screw fastening. In the event that the implant portion  21  is embedded too deep into the cortical bone  12 , the extended holding portion  22  is still extended between the cortical bone  12  and soft tissue  13 , therefore is avoided the problem to couple with the abutment  40  or  40   a  in the later process. In addition, through the extended holding portion  22 , an allowance is provided for mounting the tooth cap  30 , thereby is avoided the undesired appealing problem caused by exposing the implant portion  21  outside the gum  10  due to the uneven gum  10 , or installation difficulty caused by implanting the implant portion  21  too deep into the gum  10 . 
     As a conclusion, compared with the conventional techniques, the present invention provides features as follow: 
     1. By extending the extended holding portion outside the cortical bone by merely 3 mm to 6 mm, the problem of inadequate bone integration strength caused by occlusion interference during bone integration period can be prevented. 
     2. Compared with the conventional techniques that the implant member is extended outside the cortical bone by at least 10 mm, the invention extends the implant member by 3 mm to 6 mm, hence is avoided performing grinding adjustment caused by inadequate occlusion space between the upper tooth and lower tooth and the problems of time-consuming and effort-wasting. 
     3. The tooth cap and implant member can be coupled for use when the occlusion space is inadequate, thus provides the advantage of one-piece type dental implant structure. When the occlusion space is greater, the abutment can be provided to fasten to the coupling cavity of the implant member, thus offers the advantage of the two-piece type dental implant structure with the flexibility of changing the shape and size of the abutment. As a result, the features of the one-piece type and two-piece type dental implant structures are both available in the invention. 
     4. Dentists require preparing merely the dental implant structure with the same specification to meet the requirements of different patients, thus usability improves 
     5. By providing the auxiliary holding portion to couple the tooth cap with the coupling cavity, the contact area between the tooth cap and the implant member increases, hence the holding strength between them also is enhanced. This solves the problem that when the occlusion space between the upper and lower teeth is smaller, since the implant member is extended outside the cortical bone in a shorter length, the coupling strength between the tooth cap and the implant member is inadequate to result in loosening of the implant member from the tooth cap. 
     6. Through the extended holding portion, the coupling cavity can be formed deeper to provide firmer coupling. 
     7. Even the invention is used on an uneven gum, through the buffer of the extended holding portion, the external thread section of the implant portion would not be exposed to cause implant difficulty or aliments. 
     While the preferred embodiments of the invention have been set forth for the purpose of disclosure, they are not the limitations of the invention, and modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.