The present invention relates to a chair side apparatus for root canal treatment. More particularly, the present invention relates to an in-situ production of root canal irrigant to be used in root canal treatment.

BACKGROUND OF THE INVENTION

Since the advent of the medicine, mankind has made a conscious effort to make the surgical procedures less painful and readily available for the patients. It is a well known fact that tooth ache is one of the most potent pains due to the unyielding nature of pulp. It is due to these facts that technicians and medicos have always strived to improve the equipment which would enhance the outcome of treatment and related procedures. Root Canal Treatment (RCT) involves such procedures wherein the tooth is cleared, disinfected and resealed. The RCT procedure further involves alternate phases of clearing and flushing of the tooth with various solutions like irrigants. Such irrigants have numerous side effects and aftereffects on the exposed areas of tooth as well as vestibular regions.

Root canal is a canal or a passage that runs in the tooth and contains the pulp. The pulp consists of nerves, blood vessels, dentine forming cells and loose connective tissue. During tooth formation the pulp forms the tooth dentine. Dentine is the inner layer that forms most of the tooth hard tissue and is covered in the tooth crown with enamel and in the root it is covered with cementum. After tooth formation and eruption, the pulp's role is limited to rehydrating the tooth, transmitting pain in response to noxious stimuli and also forming a protective layer of hard tissue (reparative dentine) if the tooth is attacked by chronic /long standing irritant such as tooth decay (caries). Irrigation of the root canals with specific solutions is a part of the root canal treatment procedure. During this procedure; the root canals are irrigated with a fluid solution/paste, for example with Sodium hypochlorite, Ethylene diamine tetra acetic acid (EDTA), Chlorhexidine, Hydrogen peroxide etc. The goal is to remove the diseased tissue, debris and destroy the microorganisms. Sodium hypochlorite is the most widely used irrigant, because it dissolves pulp tissue and is a potent anti microbial agent. Sodium hypochlorite does not remove smear layer, so it is combined with EDTA which acts on inorganic matter as a chelating agent, removes smear layer.

One of the greatest complications of root canal irrigation is leakage of these irrigant fluids, through the tooth apex into the periapical tissues. Sodium hypochlorite when extruded beyond the apex causes severe pain, swelling and necrosis of the periapical tissues. Its use is not indicated in incompletely formed roots. It is purchased and stored. Any spillage during handling causes bleaching of the clothes. Its vapor can be an irritant to the eyes. Since it is corrosive in nature, root canal instruments /files become more prone to mechanical breakdown. Many agents have been tested and subsequently rejected in favor of Sodium hypochlorite.

The need remains for a treatment system that delivers a treatment or irrigation solution alternative to Sodium hypochlorite, having advantages at par with Sodium hypochlorite and still overcoming its disadvantages of toxicity caused when it extrudes through the tooth apex.

The need further remains for a biologically acceptable root canal irrigant. The need further remains for a less corrosive root canal irrigant. The need further remains for a treatment system that provides ease and convenience of use for the dental practitioner and that is time-efficient and minimizes patient discomfort.

The need further remains for treatment system for effective and easy to use compositions for root canal irrigation.

The present invention fulfills these needs and provides further advantages. OBJECT OF THE INVENTION

The object of the invention is to attach an apparatus that can produce a non toxic chemical irrigant.

Still another object of the invention is in-situ production of a root canal irrigant.

Still another object of the invention is in-situ production of a biologically acceptable root canal irrigant.

Still another object of the invention is to attach an apparatus that has a chemical irrigant less toxic and corrosive than the existing ones.

Still another object of the invention is to produce a non toxic root canal irrigation solution alternative to sodium hypochlorite.

Still another object of the invention is to obviate the requirement of stocking of effective irrigants. Still another object of the invention of the invention is to obviate the irrigants which are biologically unacceptable and toxic in nature.

Still another object of the invention is to provide an economical, and ready to use treatment option.

Yet another object of the invention is to provide a safe and painless treatment. SUMMARY OF THE INVENTION

The invention relates to a chair side apparatus for in-situ production of root canal irrigant to be used during the root canal treatment. The invention relates to the ease of production of the irrigant that is less toxic and less corrosive in-vivo. The invention addresses the need of such unit that is easy to use, economical as compared to other counterparts and comparatively safe. It saves time as it is a self sufficient unit that can produce the irrigant as and when required.

The chair side apparatus is disclosed for in situ production of a highly efficient and biologically safe irrigant. The apparatus comprises at least two electrolytic chambers, at least two inert metal electrodes, a connecting chamber meant to connect the electrolytic chambers, and a selectively permeable membrane in the said connecting chamber; wherein the said electrolytic chambers are separated by metal plates & membrane in said connecting chamber and wherein the said membrane and plate separate the solutions of the said chambers. The electrodes are connected to a direct current source. The chambers have outlets to allow their solutions to be collected by the user during the procedure/ Further, the chambers have inlets in the form of sliding plates or orifices. DESCRIPTION OF DRAWINGS

Figure 1 describes the chair side apparatus for in situ production of irrigant for root canal treatment. The device comprises two electrolytic chambers (6 & 14) containing electrodes (3 & 4), the said chambers are connected with connecting chamber (9). The said connecting chamber (9) has shutter (7) and shutter (8) having selectively permeable membrane. Each chamber (6 & 14) has outlet (10) which can be closed or opened through knob (12). Each chamber (6 & 14) can be opened to pour solutions through sliding plate (13) sliding through slit (11). The connecting chamber (9) is connected to each chamber internally via opening (5). Each electrode (3 & 4) is connected to DC source through electric wire (15). The chambers are Optionally connected to base (1) through stand (2).

Figure 2 shows the chair side apparatus with electrolytic chamber (6) opened showing electrode (4).

Figure 3 shows the chair side apparatus with electrolytic chamber (6) half opened showing electrode (4), and sliding plate (13) slid on the said chamber (6).

Figure 4a shows positive electrode (4) with electric wire (16).

Figure 4b shows negative electrode (3) with electric wire (15).

Figure 5a describes shutter (7) with opening (17).

Figure 5b describes shutter (8) with selectively permeable membrane (18).

Figure 5c describes shutter (8) without opening.

Figure 6 shows the observations of Example 1 & 2 compared after treatment with the solution produced from the disclosed apparatus and control solution respectively. Figure 7a shows the observations of Example 3 wherein the microbial growth is visible in the control sample.

Figure 7b shows the observations of Example 4 wherein no microbial growth is visible in the sample treated with the solution produced from the disclosed apparatus.

DETAILED DESCRIPTION

A tooth is composed of several components: enamel, dentin, cementum, and pulp. Every tooth has at least one canal that contains pulp tissue which is commonly referred to as the nerve of the tooth. When a tooth is exposed to trauma or decay, the tooth may get inflamed or infected. The tooth requires a root canal (Endodontic) treatment in order to prevent the tooth from being extracted.

The first step involves creating an access opening in the top of the tooth so that the pulp chamber can be accessed.

The second step involves cleaning and shaping the canals to remove all the dead and infected tissue after which the canals are filled. This is achieved by instruments, called files and reamers to shape the canal mechanically. Disinfection is achieved by chemical agents called irrigants- pastes and solutions. While instrumentation of the walls of the root canal is done the dentinal tubules on the walls gets blocked, which means the tubules in the dentin are blocked by a smear layer, within which bacteria are entrapped, which can in future infect and cause failure of the root canal treatment. Irrigation intends to:

1. Remove infected pulp tissue;

2. Remove smear layer; and

3. Kill bacteria. The most widely used irrigant is Sodium hypochlorite (0.5-5.25%). The worldwide use of sodium hypochlorite as a root canal irrigating solution is mainly due to its efficacy in pulp dissolution and antimicrobial activity.

Sodium hypochlorite exhibits a dynamic balance as is shown by the reaction:

NaOCI + H ₂ 0 NaOH + HOCI <-» Na ⁺ + OH ^" + H ⁺ + OCI ^"

It can be observed that sodium hypochlorite acts as an organic and fat solvent degrading fatty acids, transforming them into fatty acid salts (soap) and glycerol (alcohol) that reduces the surface tension of the remaining solution. This is technically referred to as SAPONIFICATION REACTION.

Sodium hypochlorite neutralizes amino acids forming water and salt. This is known as NEUTRALIZATION REACTION in the state of the art.

With the exit of hydroxyl ions, there is a reduction of pH. Hypochlorous acid, a substance present in sodium hypochlorite solution, when in contact with organic tissue ¹ acts as solvent, releases chlorine that combines with the protein amino group, and forms chloramines. This is referred to as CHLORAMINATION REACTION.

Hypochlorous acid (HOCI ) and hypochlorite ions (OCI ) lead to amino acid degradation and hydrolysis. The chloramination reaction between chlorine and the amino group (NH) forms chloramines that interfere in cell metabolism. Chlorine (a strong oxidant) presents antimicrobial action inhibiting bacterial enzymes leading to an irreversible oxidation of SH groups (sulphydryl group) of essential bacterial enzymes.

Thus sodium hypochlorite is a good antimicrobial agent, however, the risk associated with its use is the harmful effect caused when it extrudes beyond the tooth apex. It leads to severe periapical pain, swelling and necrosis— damaging the vital tissues. In addition, it bleaches clothing when spilled; causing damage and its odor is less acceptable to patients.

The present invention and the method of in-situ production of root canal irrigant overcome this risk as it is made from salt solution. Since the chambers are separated, the composition of the solution in. such chambers will be different from each other. These solutions collected are alternatively used during the RCT procedure; after which even if they extrude beyond the apex, they would combine and form salt solution again which is biologically acceptable.

The chair side apparatus is disclosed for in situ production of a highly efficient and biologically safe irrigant. The apparatus comprises at least two electrolytic chambers, at least two inert metal electrodes, a connecting chamber meant to connect the electrolytic chambers, and a selectively permeable membrane in the said connecting chamber; wherein the said electrolytic chambers are separated by metal plates & membrane in said connecting chamber and wherein the said membrane and plate separate the solutions of the said chambers. The electrodes are connected to a direct current source. The chambers have outlets to allow their solutions to be collected by the user during the procedure. Further, the chambers have inlets in the form of sliding plates or orifices.

Detailed Description of Components:

Electrolytic Chambers: The disclosed invention comprises at least two electrolytic chambers separated by a semi-permeable membrane. The chambers consist of PVC or any other transparent or non transparent material. The chambers have capacity of more than 50 ml. The chambers as described in the figures have a sliding lid on the top enabling the user to pour the respective solutions. The chambers further have a means for letting the electrolyte out of the chamber once the electrolysis process is complete. Electrodes: The disclosed invention further comprises at least two electrodes. The electrodes are made up of inert metal selected from the group of silver, gold, platinum, tungsten and alloys thereof.

Electrolyte: There are used different electrolytes in the anodic and cathodic chambers of the disclosed invention. In cathode chamber, distilled water is used as electrolyte. On the other hand, in the anodic chamber saline solution acts as electrolyte. The saline concentration ranges from 5% to 25% preferably in the range below 15%.

Connecting Chamber: The electrolytic chambers in the disclosed invention are connected through a connecting chamber. The said connecting chamber is made-up of PVC or any other transparent or non transparent material. The connecting chamber has capacity of at least 20 ml. The connecting chamber has two openings wherein, in one opening a shutter containing selectively permeable membrane is inserted and in the other another shutter with or without orifice is inserted as per the requirement during the procedure.

Selectively Permeable Membrane: The membrane in the disclosed invention is any semi - permeable membrane, preferably a proton permeable membrane. Such a semi permeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen. Their essential function is the separation of reactants and transport of protons. The membrane is selected from the group of PVDF (polyvinylidene fluoride), pure polymer membranes, polyaromatic polymers, partially fluorinated polymers or from composite membranes where other materials are imbedded in a polymer matrix. Proton exchange membranes are primarily characterized by proton conductivity, methanol permeability and thermal stability. The membrane is selected with pore size in range of 0.45 micrometer.

Mode of Use: To prepare the irrigant, the electrolytes are poured in the respective chambers, that is, distilled water in the cathode and saline in anode. The shutter containing the selectively permeable membrane is put in one opening of the connecting chamber and the shutter with orifice is put in another opening of the said chamber. The electrolysis is performed at 10.8V DC, 500mA current for a time period in the range of 8 - 20 minutes for 50ml capacity chamber. Once the electrolysis is completed, the shutter with orifice is replaced with the shutter without orifice. The solutions from respective chambers are then used alternatively during the treatment procedure. The anodic solution is used as irrigant and the cathodic solution is used as cleansing agent.

Chemical Reactions: When a circuit is established and current is passed through, the following reactions will take place:

In the cathode compartment, Water (H ₂ 0) splits into H ⁺ and OH

In the anode compartment NaCI + H ₂ 0 split into Na ⁺ and OH ^' , H ⁺ _; CI ^"

As the membrane is proton permeable Na ⁺ and H ⁺ cross the membrane and enter into the cathode compartment.

Thus the cathode compartment contains Na ⁺ ' H ⁺ and OH ~

Now, Na ⁺ is unstable and thus forms NaOH by reacting with OH ^" . Sodium hydroxide will be beneficial during the procedure as it has detergent properties which are useful in cleansing the root canal. This solution is reducing in nature.

In the anode compartment H ⁺ CI ^" , OH ^" ions are present. CHLORINE IS EVIDENT IN THIS SOLUTION BY ITS ODOR. These ions react with each other forming OCI ^" , HOCI ^' , Cl ₂ etc. These molecules are oxidizing in nature. They have properties similar to sodium hypochlorite which is extensively used as an irrigant, and shows anti microbial action.

The purpose of this invention is to make available both the solution contained in anode compartment as well as in the cathode compartment for root canal irrigation. The solution obtained at the positive (anode) terminal is strongly anti microbial due to the presence of chlorine and its derivatives - (hypochlorite ions, Hypochlorous acid etc) and shows properties similar to sodium hypochlorite. The pH of this solution is 6.5 - 7.

The solution collected at the cathode contains sodium hydroxide and aids in cleansing. The solution is alkaline with pH 8 - 10.

The idea is to use both the solutions alternatively in the root canal while cleaning and shaping, with a final rinse with the solution collected at cathode.

Since the solutions contain molecules in their active form, the reaction in the canal is immediate and effective.

Moreover, even if the solutions enter the periapical tissues, the solutions mix with each other forming saline again, saline is biologically acceptable and there are no flare ups.

The active ions which are responsible for the antimicrobial action of Sodium hypochlorite are also present in the solution collected at the anode in the present invention, thus renders the same antimicrobial properties in this solution making it as good as sodium hypochlorite.

Sodium hypochlorite does not remove smear layer, so it is combined with EDTA which acts on inorganic matter as a chelating agent, and thus removes smear layer. The solution collected at the cathode in the present invention shows cleansing action due to its detergent properties. Still the use of EDTA is recommended with rotary Endodontics (i.e. using files by rotating it with a motor not hand) for lubrication. (Lubrication reduces breakage of instrument in canal).

After removal of smear layer, the solution collected at anode is used again, as better penetration into dentinal tubules is facilitated.

) In an embodiment the chair side apparatus for in - situ production of root canal irrigant comprises of:

a. two electrolytic chambers having inlet and outlet;

b. two electrodes, one in each electrolytic chamber;

c. a connecting chamber connecting the said electrolytic chambers; d. a selectively permeable membrane in the said connecting chamber;

e. a shutter without opening; and

f. a shutter with opening;

wherein the said electrodes are connected to a DC source; the said shutters are removable and replaceable with each other; the said shutter with opening is placed in the connecting chamber during electrolysis; and the said shutter without opening is placed in the connecting chamber after completion of electrolysis.

In another embodiment of the disclosed invention the chair side apparatus the electrolytic chambers are made-up of PVC, glass or any other transparent or non transparent material.

In yet another embodiment, the said electrolytic chambers have capacity of more than 50 ml of electrolytic solution and an opening means for letting out the electrolyzed solution.

In yet another embodiment the said electrodes are made up of inert metal selected from the group of silver, gold, platinum, tungsten and alloys thereof.

In another embodiment of the invention distilled water is used as electrolyte on cathode and saline solution of concentration ranging from 5% to 25% is used as electrolyte on anode.

In yet another embodiment the said connecting chamber has two slit - openings wherein, a. in one opening the shutter containing selectively permeable membrane is inserted;

b. in the other opening the shutter with orifice is inserted during electrolysis; and

c. the shutter with opening is replaced with the shutter without orifice after completion of electrolysis.

In another embodiment the said selectively permeable membrane is any semi - permeable membrane, preferably a proton permeable membrane.

In a preferable embodiment

a. the electrolyzed solutions from the anodic chamber has anti microbial and irrigant activity;

b. the electrolyzed solution from the eathodic chamber has cleansing activity; and

c. the electrolyzed solutions from respective chambers are used alternatively.

In another embodiment the said apparatus can be customized according to the dexterity of the dentist and the ₍ clinical apparatus.

In yet another embodiment the method of in - situ production of root canal irrigant comprises of the following steps:

a. inserting the membrane containing shutter and the shutter with orifice in , the connecting chamber;

b. pouring the electrolytic solutions in respective chambers through inlets; c. connecting the electrodes to a DC source;

d. electrdlyzing the solutions for duration ranging from 5 - 20 minutes;

e. replacing the shutter with orifice with the shutter without orifice; f. disconnecting the electrodes from the DC source; and g. dispensing the electrolyzed solutions alternatively from the respective chambers.

Example 1

Cleansing Activity of the Control Solution

Ten extracted human maxillary anterior teeth were collected, stored, disinfected and handled as per the recommendation and the guidelines laid down by Occupational Safety and Health Administration (OSHA) and Center for Disease Control (CDC). The canals prepared in the following manner:

• The apical foramen of each tooth was prepared to size 40 using conventional technique and irrigating was done with 2.5% Sodium Hypochlorite solution after the use of each file.

• 20 ml of Sodium Hypochlorite solution was used for each tooth.

• · A final flush of irrigation was carried out with EDTA.

• At the end, all the canals were irrigated with saline and dried with, absorbent paper points.

• Roots were split longitudinally, prepared for Scanning Electron Microscope investigation.

Example 2

Cleansing Activity of Irrigant Produced from the Disclosed Invention

Ten extracted human maxillary anterior teeth were collected, stored, disinfected and handled as per the recommendation and the guidelines laid down by Occupational Safety and Health Administration (OSHA) and Center for Disease Control (CDC). The canals prepared in the following manner: • The apical foramen of each tooth was prepared to size 40 using conventional technique and irrigating was done with solution from anode chamber after the use of each file.

• 20 ml of anodic solution was used for ^' each tooth.

• A final flush of irrigation was carried out with 20 ml of solution from cathode chamber.

• At the end, all the canals were irrigated with saline and dried with absorbent paper points.

• Roots were split longitudinally, prepared for Scanning Electron Microscope investigation.

Example 3

Antibacterial Efficacy of Control Solution

Ten extracted human maxillary anterior teeth were collected, stored, disinfected and handled as per the recommendation and the guidelines laid down by Occupational Safety and Health Administration (OSHA) and Center for Disease Control (CDC).

Pre treatment and Infestation of Samples:

• The apical 5 mm and two thirds of the crown were cut off with a rotating diamond disk in a straight hand piece at slow speed.

• A # 10 round bur was used to enlarge the root canal of the middle segment to standardize the inner diameter of the canal.

• The smear layer was removed by irrigating the canals with 10% citric acid.

• The segments were sterilized by autoclaving at 121 °C for 20 minutes. This was repeated three times.

• The segments were placed in Trypticase soy broth containing a culture of E .faecalis ATCC29212 (1.5 X 10 ⁸ Colony forming units / ml) which correspond to 0.5 Mc Farland units and incubated at 37 °C for 5 days. The broth was replaced with fresh broth containing cultures of E.faecalis (1.5 X 10 Colony forming units / ml) on the third day. .

• A sample was taken on the first, third and fifth day and cultivated on blood agar > plates to confirm the purity of E .faecalis in the inoculum.

• After 5 days, the specimens were taken out from the broth and the canals were blotted dry with sterile paper points.

Study Protocol:

• Each canal was prepared manually with a new sterile # 40 Hedstrom file while using, sterile saline solution as the working solution. The canal was finally rinsed with sterile saline solution. The teeth were immersed in sterile saline for five minutes.

• Finally, the canals dried with sterile absorbent points. After which a sterile Hedstrom file/ was used to manually scrape the dentin from canal wall. The dentin removed from the canal was collected on pre weighed sterile aluminum foil.

• The weight of dentinal shavings was measured in each case and then the shavings transferred to 1 ml of trypticase soy broth in a test tube.

• The contents were shaken up in the test tube and using a sterile metal loop the sample was streaked on trypticase soy agar plates and incubated at 37 °C for 24 hours. ,

• The same procedure was repeated for every sample.

• After 24 hours; the colony forming units were counted.

• Using the recorded weight of dentin shavings, the number of colony forming units per mg was calculated.

Observations

WEIGHT OF THE CFU/ml CFU/mg

SAMPLE No. OBTAINED DENTINAL

SHAVINGS(mg) X 100 X 100 1. 1.6 165 103.12

2. 1.5 182 121.33

3. 1.7 148 87.05

4. 1.7 125 73.52

5. 1.8 157 87.22

6. 1.4 140 100

7. 1.9 174 91.57

8· , 1.3 172 132.30

9. 1.8 163 90.55

10. 1.8 150 83.33

Example 4

Antibacterial Efficacy of Irrigant Produced from the Disclosed Invention

Ten extracted human maxillary anterior teeth were collected, stored, disinfected and handled as per the recommendation and the guidelines laid down by Occupational Safety and Health Administration (OSHA) and Center for Disease Control (CDC).

Pre treatment and Infestation of Samples:

• The apical 5 mm and two thirds of the crown were cut off with a rotating diamond disk in a straight hand piece at slow speed.

• A # 10 round bur was used to enlarge the root canal of the middle segment to standardize the inner diameter of the canal.

• The smear layer was removed by irrigating the canals with 10% citric acid.

• The segments were sterilized by autoclaving at 121 °C for 20 minutes. This was repeated three times. • The segments were placed in Trypticase soy broth containing a culture of f .faecalis ATCC29212 (1.5 X 10 ⁸ Colony forming units / ml) which correspond to 0.5 Mc Farland units and incubated at 37 °C for 5 days. The broth was replaced with fresh broth containing cultures of E.faecalis (1.5 X 10 ⁸ Colony forming units / ml) on the third day. .

• A sample was taken on the first, third and fifth day and cultivated on blood agar plates to confirm the purity of E .faecalis in the inoculum.

• After 5 days, the specimens were taken out from the broth and the canals were blotted dry with sterile paper points.

Study Protocol:

• Each canal was prepared manually with a new sterile # 40 Hedstrom file while using solution from cathode chamber as the working solution. The canal was finally rinsed with solution from anode chamber. The teeth were immersed in solution from anode chamber for five minutes.

• Finally, the canals dried with sterile absorbent points. After which a sterile Hedstrom file, was used to manually scrape the dentin from canal wall. The dentin removed from the canal was collected on pre weighed sterile aluminum foil.

• The weight of dentinal shavings was measured in each case and then the shavings transferred to 1 ml of trypticase soy broth in a test tube.

• The contents were shaken up in the test tube and using a sterile metal loop the sample was streaked on trypticase soy agar plates and incubated at 37 °C for 24 hours.

• The same procedure was repeated for every sample.

• After 24 hours; the colony forming units were counted.

• Using the recorded weight of dentin shavings, the number of colony forming units per mg was calculated. Observations

WEIGHT OF THE CFU/ml CFU/mg

SAMPLE No. OBTAINED DENTINAL

SHAVINGS(mg) X 100 X 100

1. 1.8 - -

2. 1.5 -

3. 1.9 - -

4. 1.6 - -

5. 1.3 - -

6. 1.8 3 1.66

7. 1.6 1 - 0.625

8. 1.5 - -

9. 1.8 - -

10. 1.8 - -