Abutment screw remover

Abstract

2.1. Technical problem: Failure to remove an abutment screw (F) in a dental implant is a dreaded complication. Failure to remove the screw fragment can have serious consequences. When removing the screw fragment, care must be taken to avoid damaging the implant body. Existing rescue sets use left-handed rose burs or diamond bits, which create a central hole and then use a mandrel to remove the screw by turning counterclockwise. This doesn't work with ceramic screws, such as those from Z-Systems, systems Z5-BL and Z5-TL, due to the material's properties. A central hole is impossible due to the hardness of the material, and the screw is only 1.35 mm in diameter. 2.2. Solution to the problem: Screw removal is possible using a single procedure, a hand-held instrument. A gap remains in the upper part of the broken screw (F) between the implant body (E) (2.0 mm at this point) and the screw (F) (outer diameter 1.35 mm). The abutment screw remover (D), which grips and clamps the screw, allows the screw to be removed by turning it counterclockwise. The instrument: The instrument consists of a round pin with a diameter of 2.5 mm. It tapers at the lower end and has a 1 mm deep conical bore with a diameter of 1.3 to 1.4 mm.

Description

1. Previews:It is a rare but feared complication if an abutment screw breaks in a dental implant. Resupply cannot be made as long as the broken screw fragment is not removed. If this fails, the implant remains useless, the patient is not cared for and must accept restrictions. When removing the screw fragment, care must be taken that the implant body is not damaged. To make a new supply possible. Frequently, the view and accessibility to the screw are restricted, which further reduces the prospects of success. In order to carry out a new supply, if the screw removal fails, the implant would even have to be removed and a new one inserted, with all consequences with regard to psychic stress, time expenditure, pain, financial expenditure and the damage to the bone, possible nerve damage, adhesion and the like. Thus, the success has an enormous significance for the patient and the handler.In this case, Research sets have been developed by some companies. These work on the principle that left-rotating rose drills or diamonds are used. In order for these to grip, a central bore is usually required, which is placed in the middle of the broken-off screw with the aid of guide aids. A mandrel, optionally with a thread, is then introduced into the resulting cavity, which mandrel wedges itself with the screw. In this way, the screw is unscrewed.This functions in some cases well with titanium screws, but can also be problematic.In the case of ceramic screws, for example from Z-Systems, Z5-BL and Z5-TL systems, this does not work because of the material nature. A central bore is not possible because of the hardness of the material, and the screw is only 1.35 mm in diameter. Also, left-handed diamond instruments have failed in my hand, possibly also because of the high hardness. Thus, the drills slide and do not grip.2. Problem Solving by the Invention:However, screw removal is possible with a simple method / hand instrument that can be easily manufactured. In two cases that have occurred hitherto and in other cases known to those skilled in the art, the screw (F) is fractured above the thread, respectively. The thread is 2 mm long. However, only 1 mm goes beyond the abutment. Consequently, in the upper part of the screw which has been broken off, a gap remains between implant body (E) (at this point 2.0 mm) and screw (F) (outer diameter 1.35 mm). With an instrument (D) which at this point engages around the screw and clamps it (see FIG. 2 ), the screw (F) can be removed in a leftward rotating manner. In cases where parts of the abutment have fractured and remained in the implant, they must be removed beforehand with a scale.3. The instrument (see FIG. 1):I have made an instrument - the abutment screw remover (D) - which consists of a round pin of steel with 2.5 mm diameter and 22 mm length. In the upper part, one could corrugation the instrument or apply a handle (B) in order to have a secure hold under intraoral conditions. At the lower end there is a 1 mm deep conical bore. The opening would have to have a diameter of 1.4 mm at the bottom of about 1.3 mm. A bore similar to that for an allen key could also be used and widened in the opening region until the broken-off screw is overlapped from the outside. In the region of the lower end, the instrument must be reduced in diameter over a length of at least 2 mm. In the region of the lower 0.6 mm, the outer diameter must be 1.9 mm in order that it can be introduced into the narrow gap between implant body and screw. A wall thickness of 0.25 mm remains with a bore of 1.4 mm. The friction can be strengthened in the interior of the cone (C) by milling in a left-hand thread or by milling in sharp edges or else merely roughening it. In the event of wear, an adhesive wax could also be introduced into the conical opening. Since the screws are tension screws and are no longer under tension after fracture, they can be removed by this method.4. List of reference numbers:A Allen head or the like B Perforated outer side for better retention C Strong inner side D Abutment screw remover E Implant body F Fractured screw

Claims

Instrument / Method for Removing Fractured Screws from Dental Implants Having a Gap Around the Fractured Element. The instrument engages around the screw from the outside with a conical opening at the lower end. The cone causes the screw to jam. This can then be removed in a leftward rotating manner.The instrument / method of claim 1 may optionally be provided with additional resistive elements (e.g. left hand thread, roughening, adhesive) in the internal cone to increase friction.The instrument of claims 1 and 2 was designed with the indicated dimensions for the Z5-BL implant and the Z5-TL implant from Z-Systems. However, the method can also be used in principle for other implant systems and other screw diameters, provided that a gap exists around the screw fragment. Optionally, these instruments can be manufactured with different diameters for the typical implant screw diameters (e.g., 1.4 mm and 1.6 mm).

Images