Patent Application
20190247146
Positive pressure irrigation is the most commonly used irrigating technique in endodontics today. This can be attributed to many factors which include ease of use, low cost, and training techniques in dental institutions. This technique has limitations which include high pressure during use (13) inability to safely irrigate the apical third of the root canal system without causing hypochlorite (NaOCl) accidents (9). The most important limitation is the inability to utilize high volume of irrigants (8). Negative pressure irrigation is a technique that involves circulating the irrigating solution throughout the entire working length of the root canal system. The preparation of the root canal system is critical for the smooth functioning of the negative pressure irrigating apparatus. A hybrid instrumentation technique (6) utilizes TF adaptive files for the coronal preparation and light speed instrumentation system for the apical 5 mm of the root canal system. The use of light speed creates a parallel preparation with minimal apical transportation (2, 3) removing all apical anatomical interferences for the smooth movement of the negative pressure micro cannula to working length thereby preventing it from bending as well as clogging up. Negative pressure irrigation has other advantages which include removal of the apical vapor lock (7), increased flow of irrigants through the apex (8), drainage of large apical cysts (12), improved removal of the smear layer (11) and decreased bacteria counts in the apical third of the root canal system (10).
During the In Vivo use of the negative pressure irrigating system it was noticed that the flow of the irrigant slowed down as it approached the apical constricture and actually stopped as it approximated the root apex. This observation seemed to happen consistently and hence it was decided to see whether we could utilize this technique in an In Vitro setting as a way to develop a formula to confirm final working length. There are many ways of determining working lengths which include apex locators, 3D CBCT length measuring techniques, working length x rays. The limitation of 3D CBCT length measuring technique is that it cannot give us the location of the apical constricture. The use of the apex locators involves the utilization of the canal probe for final length measurements thereby risking the introduction of the contaminants as well as debris formation once the root canal system has finally rinsed. The two dimensional x ray technique is not accurate in areas of the mouth that are hard to reach and difficult to interpret when anatomical structures approximate the root apices.
Further, the inventor has identified a long felt, unmet need in the field, the ability to use combined positive pressure and negative pressure irrigation with a single handpiece operated by a single operator.
In one general aspect, the invention relates to a handpiece for simultaneously irrigating and suctioning during an endodontic procedure, the handpiece comprising a handle portion comprising a first fluid line and a second fluid line passing into a head portion comprising an outlet for the first fluid line and an inlet for the second fluid line.
Embodiments may comprise one or more of the following features. For example, the first fluid line and the outlet for the first fluid line may form fluid tight a connection and the second fluid line and the inlet for the second fluid line form a fluid tight connection. The handpiece may further include a third line passing between the handle portion and the head portion, wherein the third line comprises a fiber optic cable and the head portion includes a light source. The handpiece may further include a fourth line passing between the handle portion and the head portion, wherein the fourth line provides high pressure air to turn the head.
The handpiece may further include an irrigation tube mountable to the inlet for the second fluid line at the head portion. The irrigation tube may have a channel passing between a first open end and a second open end. The irrigation tube may be made of stainless steel, a nickel titanium alloy, aluminum, or a polymer.
The handpiece may further include a console having a first pump, a second pump, a first chamber, and a second chamber, wherein the first pump creates a negative pressure to suction fluid into the first chamber, the second pump creates a positive pressure to pump fluid from the second chamber. The console may further include a mounting end for mounting a cable from the console to the handpiece to provide a fluid connection between the first fluid line in the handpiece and the second pump and provide a fluid connection between the second fluid line in the handpiece and the first pump, whereby operating the console with the handpiece provides fluid through the second fluid line in the handpiece and suction fluid through the first fluid line in the handpiece.
In another general aspect, the invention relates to a method for irrigating during a dental or endodontic procedure. The method includes:
providing a handpiece for simultaneously irrigating and suctioning during the dental procedure, the handpiece comprising a handle portion comprising a first fluid line and a second fluid line passing into a head portion comprising an outlet for the first fluid line and an inlet for the second fluid line;
providing a console having a first pump, a second pump, a first chamber, and a second chamber, wherein the first pump creates a negative pressure to suction fluid into the first chamber, the second pump creates a positive pressure to pump fluid from the second chamber;
forming a first fluid connection between the handpiece and the console, the first fluid connection being between the first fluid line in the handpiece and the second pump, whereby operating the console with the handpiece suctions fluid through the first fluid line in the handpiece; and forming a second fluid connection between the handpiece and the console, the second fluid connection being between the second fluid line in the handpiece and the first pump, whereby operating the console with the handpiece provides fluid through the second fluid line in the handpiece.
Embodiments of the method may include one or more of the following features. For example, the handpiece may further include an irrigation tube mounted to the inlet for the second fluid line in the head portion, the irrigation tube having a first opening, a second opening and a channel between the first opening and the second opening. The method may further include inserting the irrigation tube into a cavity while simultaneously irrigating and suctioning through the handpiece.
The cavity may be a root canal formed in an endodontic procedure. The dental procedure may be a root canal procedure.
One or more of the handpiece and the console may further include a sensor for detecting air bubbles or fluid flow and detecting air bubbles or a reduction in fluid flow causes emission of an audible or visual signal.
The method may further include advancing the irrigation tube into the cavity until air bubbles are drawn into the irrigation tube. The method may further include advancing the irrigation tube into the apical third of the root until reaching the apical vapor lock.
The method may be characterized by operation of the handpiece by a single operator.
According to the method, the handpiece may further include a third line passing between the handle portion and the head portion, wherein the third line comprises a fiber optic cable and the head portion includes a light source. According to the method, the handpiece may further include a fourth line passing between the handle portion and the head portion, wherein the fourth line provides high pressure air to turn the head.
This invention was developed as the result of observations made during the use of micro cannula in the endo vac system in an endodontic procedure. It was observed that as the micro cannula approached the working length, the flow of the irrigant slowed down and stopped. Based on this observation, a study was conducted. In the study, fifty extracted teeth were utilized to study the invention and associated technique. The teeth were accessed, and working length were determined with a hand file introduced to 0.5 mm from the apex and x rays were taken. The teeth were then instrumented with a hybrid technique utilizing hand instruments, TF adaptive files and light speed instrumentation. Teeth were then irrigated utilizing negative pressure technique. As the micro cannulas approached the apical constricture, the flow of fluid changed in the irrigating system. First the fluid flow reduced and then bubbles were released as the micro cannulas approached the root apex. The length was then recorded and compared to the initial working length measurement. It was determined that working length can accurately be reproduced using a formula of working length minus 0.5 mm.
Materials and Methods of the Study: Fifty extracted teeth were retrieved from a local oral surgeon. The teeth included mature teeth, immature teeth, anteriors, premolars and molars. Based on the teeth received, they were divided into three groups based on the integrity of the apical morphology. The teeth were left in a jar of water to keep them hydrated. One day before the root canal preparation the teeth were mounted in a silicone ice cube tray, utilizing a mix of fifty percent of Plaster of Paris and fifty percent clear acrylic resin powder. As illustrated in
The teeth were accessed using 330 pear-shaped burrs, to the root system. The access was done utilizing a surgical operating microscope. Working length was determined by introducing a file to resistance and x rays were taken utilizing a wax x-ray jig. Working length was 0.5 mm from the radiographic apex (2, 3). The root canal system was instrumented using TF adaptive files to length followed by light speed instrumentation to a size of 40 to 50 (8) as the final LSX size depending on the tooth (
Referring to the x-ray illustrations of
Positive Control—Fluid slowed down and bubbles were released as the micro cannula approached the root apex.
Negative Control—No fluid flow was seen through the tubes without the use of the micro cannula.
Results: (a) Twenty three (23) teeth WLEV (46%) were 0.5 mm beyond the apex. These teeth had well-formed apices. (b) Twenty three (23) teeth WLEV (46%) were 1 mm beyond the apex. These teeth had resorbed apices. (c) Four (4) teeth (8%) were grossly over extended. These included blunder buss apices and cracked teeth.
(0.5 mm-1 mm)
Discussion: To the knowledge of the inventors, this technique has not been performed before, as such there were no guidelines to follow for developing an accurate study model. A significant challenge encountered in the study was in obtaining teeth that had intact apical anatomy, i.e., no apical resorption, no blunder buss canal and no fractured teeth. The teeth that had calcified canals, upon instrumentation developed cracks. The teeth with open apices were inconsistent with this technique. This was attributed to the fixed diameter of the micro cannula. The teeth that had consistent results had perfectly rounded apices with no apical resorption and a visible canal system. These teeth had stable apical constrictures which acted as a seal for the micro cannula. When the micro cannula exited the constricture, negative pressure was lost and the bubbles were released from the bead. Teeth that had resorbed apices resulted in loss of apical constricture and hence the entire micro cannula tip (0.7 mm) had to exit the root end. The teeth that had fractures and open apices could not provide a seal apically and hence the significant difference in length (up to 5 mm in one case).
During the length determination with negative pressure, observing the change in flow pattern (escape of air bubbles) needed the use of microscope. When the rubber stop was placed in contact with the reference point, the micro cannula sometimes moved, hence the need for steady hands.
This technique eliminates the need to reintroduce a probe into the root canal system for final length with the apex locator. Once the length is confirmed the micro cannula is used to remove the excess irrigating solution prior to drying with paper points. This eliminates any further debris creation with the use of a probe. This technique is highly effective in areas of the mouth that are hard to reach or teeth that are extremely long anatomically, i.e., (31 mm) and above. Some clinical cases have been presented to provide a sense of what can be accomplished using this technique. The use of light speed keeps the preparation of the canal conservative and eliminates apical restriction to the movement of the micro cannula. Without light speed introduced into the preparation the micro cannula was seen to bend prematurely or to come apart during use. It also clogged up frequently making it hard to have consistent flow. These observations were made in an In Vivo setting.
Negative pressure only accounts for vertical fluid movements but no lateral circulation between the canals.
The inventors concluded that the determination of the working length is more accurate when more than one technique is used, i.e., apex locators and working length x rays. This is an additional technique that if refined can eliminate the need for x ray technique. It also has an added advantage of eliminating the debris in the zone between the apical constricture and the radiographic apex, a distance of which varies from 0.5 mm up to 2 mm from the apex. In the right hands, using a strict instrumentation technique as mentioned above this working length confirmation can be used as an adjunct to length confirmation prior to obturation. In intact apical morphology subtracting a 0.5 mm from the length after the fluid stops moving gives us the final working length. Care should be taken in situations with long standing periapical pathology as this could lead to inconsistent length measurements. This technique should not be applied in teeth with open apices.
Referring to
The positive pressure connector 135 and the positive pressure outlet irrigation tube 115 are connected with a line to permit the irrigation fluid to flow through a cable to the connector 135 and out through the tube 115. The negative pressure connector 130 and the negative pressure irrigation tube 120 are connected with a line to permit the irrigation fluid to flow through the negative pressure inlet irrigation tube 120 to the connector 130.
The optional fiber optic connector 125 is used to provide a light source to the handpiece 100. The light source may be on the head 110 and used to illuminate the region in which the irrigation tube 120 is used. The head 110 can include a fiber optic cable or the like that passes from the connector 125 to a light source on the head.
The optional high pressure air inlet connector 140 can be used, if desired, to rotate the head and irrigation tube 120. During use, rotating the irrigation tube 120 may improve negative pressure irrigation of the procedure area.
The irrigation tube 120 also may include markings 146 along its length to indicate length from the distal tip opening 145 of the tube. The endodontist can use the markings to determine the depth within the tooth in a procedure.
The irrigation tube 120 can be permanently or removably attached to the head 110. For example, referring to
The tube 120 will be approximately 0.5 cm to 2 cm in length and have an outer diameter of approximately 0.05 mm to 0.1 mm in outer diameter. The tube can be made from any one of a variety of materials, including a stainless steel, aluminum, a nickel titanium alloy, or a polymer. In a preferred embodiment, the material used permits the tube to be flexible.
Referring to
As should be evident, when a first end of the cable is connected to the console 200 at mounting end 230 and the second end of the cable is connected to the handpiece at mounting end 107, negative pressure created by the negative pressure pump in its associated line will create negative pressure at the opening 145 in the irrigation tube 120, which will suction fluid into the chamber 210. Similarly, the positive pressure pump can be used to pump irrigation fluid out of the second chamber 220, through the mounting end 230, through the cable, through the mounting end 107 and through the irrigation line 115 into the procedure field.
The configuration of the chambers 210, 220 are designed to permit fluid levels to be measured. The inventors recognize the importance of ensuring that sufficient amounts of irrigating fluid are used to clean and disinfect the root, especially the apical third of the root. However, the inventors stress the importance of ensuring that whatever amount of irrigating fluid is used to clean and disinfect the root is removed from the root. To accomplish this the chambers are marked to show volumes or other measures of fluid usage and recovery. For example, if ten milliliters are used to clean and disinfect the root, approximately ten milliliters of fluid must be removed. If a hypochlorite solution is used to clean and disinfect the root, that fluid should be removed to prevent leaving fluid in the root area because such fluids are likely to cause discomfort, pain and adverse effects.
As explained above the inventors found that based on the depth within the root the endodontist will either irrigate out fluid or air bubbles. Thus, the system permits the endodontist to determine the depth of the tube 120 within the root canal. With the system being used in a procedure, fluid is pumped into the system through tube 115 and suctioned out through tube 120. As fluid builds up in the canal while the tube 120 is advanced into the canal, the tube 120 will be suctioned into the tube. Upon entering the apical third of the root where typically an apical airlock prevents complete irrigation and suctioning of the apical third, the tube 120 is expected to break the airlock and permit irrigation and disinfection of the entire canal and root.
As the tube 120 gets close to the tissue at the apex of the root, the irrigation will return bubbles rather than fluid. This permits the endodontist to avoid clogging the tube 120 with tissue and spend unnecessary time cleaning the tubing and subsequent delay of the procedure. This technique was described in the study discussed herein.
The system also permits the endodontist to irrigate in an endodontic procedure without assistance from a second person. Typically, irrigation in these procedures is a two-person requirement with one person holding the irrigation tubing and providing irrigation fluid while the second person uses negative pressure to suction out the fluid. Using the handpiece described herein, the endodontist, dentist or even dental student can irrigate, cleanse and disinfect the root canal while monitoring the irrigation to know how close the opening 145 of the tube 120 is to the root apex.
As an optional feature of the handpiece 100 and console 200, the system can include sensors to monitor the fluid returned through the negative pressure tube 120. For example, the sensor can detect one or more of air bubbles, rate of fluid flow or change in rate of fluid flow, or a change in pressure in the line, etc. that demonstrates that the fluid suctioned within the tube contains a sufficient quantity of air bubbles. Upon detecting air bubbles or a change in rate of fluid flow (e.g., reduction in rate) the console can emit an audio of visual signal. The sensor can be in the handpiece, between the handpiece and the cable, or in the console. Upon hearing or seeing the audio or visual signal, the endodontist can pull back on the handpiece or hold it in a steady position.
The endodontist also can visually check the chambers 210 and 220 to ensure that the fluid used in the procedure has been captured and removed from the patient's root canal. For example, if not as much fluid has been recovered as was used to irrigate, the endodontist would insert the tube 120 into the root canal and apply negative pressure to remove the fluid.
This application is a utility application claiming the benefit of priority of provisional patent application No. 62/457,217, filed on Feb. 10, 2017, the contents of which are incorporated herein in their entirety.
