Abstract:
An assembly for practicing sinus membrane elevation in the process of dental implant surgery comprising a balloon made of an elastomeric material and having a rounded head portion, an elongated, tubular sleeve portion and a flanged rim portion. Further provided is a balloon probe member having a stem portion with an outer screw-thread and a bore freely fitting the external diameter of the balloon tubular sleeve. A connector member is threadably receivable in the probe member and connected to a flexible pipe with a manually operable valve. For inflating the balloon a pump supplies a pressurized fluid through the pipe.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a 35 U.S.C. §371 National Phase conversion of PCT/IL2007/000543, filed May 3, 2007, which claims benefit of Israeli Application No. 175477, filed May 8, 2007, the disclosure of which is incorporated herein by reference. The PCT International Application was published in the English language. 
     BACKGROUND OF THE INVENTION 
     In the journal of Oral Implantology, Vol. XXXII No. 1 (2006) of February 2006, there has been published an article titled “Minimally by Invasive Antral Membrane Balloon Elevation Followed by Maxillary Bone Augmentation and Implant Fixation” (Dr. Efraim Kfir et al.) In the article there has been described implementation of a technique using a balloon for separating and lifting the Shneiderian membrane in order to gain more bone substrate for placement of maxillary dental implants. 
     This method has already been proposed in European Patent Application No. 1174094 published Jan. 23, 2002. 
     The general object of the present invention is to provide an apparatus for practicing this method in a safe and reliable manner. 
     It is a further object of the invention to provide a kit of parts that can be used repeatedly after autoclave sterilizations. 
     It is a still further object of the invention to ensure protection of the balloon within a dedicated probe during the insertion phase. 
     It is a still further object of the invention to provide means enabling exact extent of penetration of the balloon probe to avoid accidental rupture of the sinus membrane. 
     It is a still further object of the invention to reach sinus floor spreading-apart of over 10 mm  in all directions. 
     SUMMARY OF THE INVENTION 
     According to the invention is provided an assembly for practicing sinus membrane elevation in the process of dental implant surgery comprising a balloon made of an elastomeric material comprising a rounded head portion, an elongated, tubular sleeve portion and a flanged rim portion; a balloon probe member having a stem portion with an outer screw-thread and a bore freely fitting the external diameter of the tubular sleeve, a shoulder configured to support the said balloon flanged rim portion, and cup-shaped portion with an inner screw thread therealong; a connector member threadably receivable in said cup-shaped portion at one side and configured to be coupled to a flexible pipe at the other side thereof; a flexible pipe with a manually operable valve; and a pump for administrating a pressurized fluid through the pipe to the balloon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and additional constructional features and advantages of the invention will be more readily understood in the light of the ensuing description of a preferred embodiment thereof, given by way of example only, with reference to the accompanying drawings wherein:— 
         FIG. 1  is an exploded view of the assembly according to a preferred embodiment of the present invention; 
         FIG. 2   a  is a cross-sectional view of the assembly in an assembled position; 
         FIG. 2   b  is a detail of  FIG. 2   a  on an enlarged scale; 
         FIG. 2   c  is a detail of  FIG. 2   a  illustrating in cross-section view a portion of the tubular stem portion. 
         FIGS. 3   a  and  3   b  show a drill specially designed for use with the assembly of the present invention; 
         FIG. 4  illustrates the assembly in a preparatory stage; 
         FIG. 5  shows the balloon blowing stage; 
         FIG. 6  illustrates the stage of filling the sinus cavity below the elevated membrane with autologous fibrin; and 
         FIG. 7  shows the completed implant placing. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Starting from bottom to the top of the assembly generally denoted  10  in  FIG. 1 , there is provided a pump  12  for delivering (and discharging) a fluid. The pump  12  may be electric or manual. The fluid may be a saline liquid. 
     From the pump there extends a first stretch of flexible transparent hose  14  leading to a pressure-gauge fitting  16 . 
     A second length of hose  18  is connected to valve  20  shown in the closed position. 
     A further pipe stretch  22  leads to a connector member designated  24 . The connector  24  comprises an outer screw-threaded portion  24   a  and a preferably knurled ring-shaped shoulder  24   b . The connector member  24  is connectable, after interposing seal ring  26 , to balloon probe  28  which comprises a cup-shaped portion  28   a  and a tubular stem portion  28   b . The portion  28   a  comprises an inner screw-threaded side wall  25  and an inner base wall, constituting an inner shoulder  27 . Preferably, the portion  28   a  further has a knurled outer surface. The tubular stem portion  28   b  is of an inner diameter slightly greater than the outer diameter of balloon  30 . The portion  28   b  has an osteotomy screw-thread. 
     The inner shoulder  27  is configured to support a balloon flanged rim  30   c , as described below, when the balloon probe  28  is connected to the connector  24 , i.e. when the screw-threaded portion  24   a  of the connector  24  is threadably received in the cup-shaped portion  28   a  of the probe  28 . 
     Now, according to a major aspect of the invention, and unlike normal balloons made of thin and flappy sheet of Latex or the like rubber based materials, the balloon  30  is preferably made of Silicon rubber and in the form of a self-supporting article, having a rounded, mushroom-like, top  30   a , merging into an elongated sleeve  30   b  provided with a flanged rim  30   c . The balloon is preferably produced by a process known as “press-cure transfer and dipping” process in order to yield the following specifications:
         the mushroom head  30   a  should be of low modulus of elasticity (hardness of 16-40 shor) and high elongation factor (600%-1,300%);   the remaining portions  30   b  and  30   c  are thicker and of high modulus (50-80 shor) and low elongation factor (250%-600%);   the wall thickness of the balloon head  30   a  is about 0.2 mm ;   the wall thickness of the sleeve portion  30   b  is about 0.3 mm ;
 
Thus, the balloon  30  is self-contained, adapted to be conveniently gripped by a tongs or even by hand whenever requested, e.g. carried to or from an autoclave for sterilization between repeated uses. No strips, ties, or glue are involved as will be appreciated from the description given further below.
       

     In the assembled state ( FIG. 2   a ), the head  30   a  of the balloon  30  is slightly crimped as seen in  FIG. 2   b    
     There is further included a seal ring  32  conforming the size of the balloon rim  30   c  for tightening the rim upon coupling the connector  24  to the probe  28 . 
     Spacer rings  34 ,  36 ,  38  or more, of different widths, are included for a reason to be explained below. 
     For preparation of the sinus membrane lifting there must first be drilled an osteotomy through the alveolar crest where the maxillary dental implant needs to be placed. 
     Hence, according to an additional aspect of the present invention a special drilling bit is proposed as shown in  FIGS. 3   a  and  3   b.    
     The osteotomy generally designated  40  comprises a pointed drill  42  of about 2 mm  diameter and a length l of about 8-18 mm . Shank  44  is screw-threaded. Set rings  46  and  48  are threadable along the shank  44 . 
     Cooling water flows up the passage  50  and out of outlet  50   a.    
     Depending on the available bone thickness at the alveolar crest (which can vary between 1 mm  to 8 mm ), the operative length of the osteotomy drill  42  is preset by the pair of rings  46 , 48  tightened against each other as shown in  FIG. 3   b  in order that the tip of the drill should reach 1-2 mm  below the sinus floor. 
     The augmentation process proceeds as follows.
         (a) The remaining, thin sinus floor above the osteotomy is gently chiseled away by an osteotom (not shown).   (b) The assembly components  20 - 30  (see  FIG. 4 ) are filled with saline liquid in order to avoid air trapped inside. This is done by simply pouring the liquid into the system (when held upside-down) and then shutting the valve  20 .   (c) Spacer rings  34 ,  36 ,  38 , or any combination thereof are placed over the shoulder  28 , around the stem  28   b  so that after insertion (see below) the top thereof will extend flush with or slightly higher (say by 1 mm ) than the sinus floor. This requirement is important in order to avoid rupture of the balloon, once inflated, by sharp bone spikes which remain around the osteotomy after stage (a).   (d) The sub-assembly  20 - 30  is connected to the pump  12 , the valve  20  opened and the pressurized fluid is pumped into the balloon  30 —see  FIG. 5 . Close control should be kept over the process. Typical pressure used is about 2 ata and about 2 cc  in quantity. Monitoring is observed by X-ray or panoramic.   (e) Once the membrane lifting has reached the desired amount, say by balloon inflation of 10 mm -20 mm  in diameter, the balloon is allowed to deflate (possibly by reversing the pumping direction). It should be emphasized that the blowing of the balloon is carried out in a single, continuous process.   (f) The assembly  10  is removed from the patient, taken apart (see  FIG. 1 ) and sterilized for the next operation.       

     Now the cavity formed under the raised sinus membrane is ready to be filled with fluidized bone substance  60  (artificial or natural), e.g. by using a dedicated syringe  62  as illustrated in  FIG. 6 . 
     Following the augmentation, implant  64  can be fixed in the conventional manner as shown in  FIG. 7 . As will be noted, the overall length of the implant can reach 18 mm  and more depending on the individual conditions of each case. 
     Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be effectuated without departing from the true spirit and scope of the invention as defined in and by the appended claims.