RU2844788C1 - Method for retrograde endodontic treatment of root canals of teeth in the treatment of chronic apical periodontitis - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention refers to medicine, particularly to dentistry, and is applicable in treating chronic apical periodontitis. It involves clinical and X-ray examination and local anaesthesia. Resection of the apex of the root is carried out, including incisions of the mucous membrane in the projection of the causative tooth, cutting out and separating the mucoperiosteal flap, trepanation of the bone to visualize the apical part of the roots, curettage of pathologically changed tissues in the region of the apex of the tooth root, followed by resection of the apex of root by 3 mm from the apex, inspection of the cut surface of the root stump using 1 % methylene blue, formation of a cavity with depth of 3 mm along the channel axis using an ultrasonic tip and a nozzle for retrograde preparation, retrograde obturation with ProRoot MTA material and its sealing, reposition of the mucoperiosteal flap into place and its closure. After separation of the mucoperiosteal flap by trepanation of the bone, an osteotomy approach is created in the external cortical plate of the jaw in a projection of the apex of the root of the causative tooth, and after curettage, haemostasis is performed using collagen and adrenergic agents, wherein the resection of the apex of the root is carried out at angle of 45 degrees to the root axis, with a chamfer facing the vestibular surface, and in the cavity with depth of 3 mm formed by means of an ultrasonic head for retrograde preparation, a retrograde pre-curved rotational nickel-titanium file RaCe Evo from an alloy with controlled shape memory (CMwire), fixed in the endodontic tip, is introduced, and by moving it into the middle and mouth parts of the canal, performing the retrograde instrumental treatment with further formation of the root canal by successive application of nickel-titanium files from an alloy with controlled shape memory (CMwire), using tools from a smaller to a larger size. That is followed by a retrograde instrumental treatment to clean the root canal walls from the apical part to the mouth with reciprocating with the endodontic tool XP-endo Finisher file made of M-Wire alloy for 2 minutes with subsequent retrograde irrigation of the formed root canal from the apical part to the mouth part using an endodontic syringe filled with 0.5 % chlorhexidine bigluconate solution, retrograde root canal is dried with sterile paper pins and a retrograde bioceramic sealer is introduced into the lumen of the prepared root canal from the apical part to the mouth part using a rotary nickel-titanium file in a reverse mode, followed by retrograde cleaning of the apical part of the root canal within 3 mm from the previously introduced sealer. That is followed by a retrograde obturation of the apical part of the root canal within 3 mm with a filling material with portland cement, condensing it with a micro plugger for retrograde obturation, removing excess filling material from the section surface of the tooth stump, wherein all treatment is carried out using a dental surgical microscope and radiovisiographic examination for its control.

EFFECT: by increasing the depth of the retrograde instrumental processing of the root canal and removing the leaky obturation material in the root canal, the method allows instrumental cleaning of the root canal space at a depth of more than 3 mm while preserving the root dentin, to form an optimal shape of the root canal for irrigation and subsequent homogeneous obturation, to preserve the functional anatomical state of the tooth as a dentoalveolar organ, to improve the patient’s quality of life.

1 cl, 16 dwg, 1 ex

Description

The invention relates to the field of medicine, in particular to dentistry, and can be used in conservative surgical treatment of teeth with a diagnosis of chronic apical periodontitis and is indicated when there are missed or poorly obturated root canals with limited or no orthograde access.

One of the main tasks in endodontic treatment is instrumental and medicinal treatment of the root canal to apical constriction with subsequent hermetic obturation. Missed root canals, in case of their infection, are one of the reasons for the development of chronic apical periodontitis.

The purpose of instrumental treatment of root canals is to remove organic tissue and reduce the number of microorganisms infecting the root canal space, creating a root canal shape for high-quality irrigation and hermetic obturation. The created root canal shape should repeat the individual anatomy and maintain sufficient dentin thickness to prevent perforations and vertical root cracks.

Currently, various methods of instrumental treatment of root canals are recommended for use. For orthograde treatment of the root canal, rotary files made of various nickel-titanium alloys are used. The most popular are files made of CMwire and M-Wire alloys, which, due to their flexibility and high resistance to "cyclic fatigue", allow preserving the anatomical shape of the canal with minimal transportation.

In case of root apex resection surgery, special ultrasonic nozzles with water cooling are used for retrograde preparation of root canals and anatomical elements.

Ultrasonic retrograde preparation tips have standard working part length dimensions of 3 mm, 6 mm and 9 mm. The metal alloy does not allow these tips to bend in accordance with the canal curvature, and therefore instrumental processing is performed only in a straight line with the creation of a truncated cone shape. According to research (Yuan-Ling Ng, Kishor Gulabivala “Factors that influence the outcomes of surgical endodontic treatment”, IEJ 2023. // Posted on the Internet: https://discoverv.ucl.ac.uk/id/eprint/10163823/7/Gulabivala_Factors%20that%20in fluence%20the%20outcomes%20of%20surgical%20endodontic%20treatment_Vo R.pdf) the depth of root canal preparation during retrograde treatment is an important prognostic factor influencing the long-term outcome of root apex resection surgery.

In case of insufficient root dentin thickness, presence of bends and invaginations of the root system, the use of ultrasonic tips with a longer working part to increase the depth of root canal preparation leads to excessive removal of root dentin and transportation of the root canal with the risk of perforations and vertical cracks in the root. Rotary nickel-titanium files, which are used in orthograde preparation of root canals of teeth, are also advisable to use in retrograde preparation of missed or poorly obturated root canals of teeth.

The proposed method of retrograde endodontic treatment of root canals of teeth with nickel-titanium instruments with controlled shape memory allows combining the advantages of both the generally accepted method of retrograde preparation with ultrasonic tips and the technique of preparing root canals with endodontic files while maintaining the anatomical shape of the root canals with a simultaneous increase in the depth of instrumental treatment of the root canals.

The closest in technical essence and achieved result to the proposed technical solution is the "Method for forming access to the apical part of the roots during resection of lower jaw molars" (patent for invention RU 2655082, IPC A61B 17/00 (2006.01), A61B 18/18 (2006.01) - 18.04.2017), the description of which provides a method for instrumental and medicinal treatment of the root canal of a tooth, consisting in making an incision of the mucous membrane under local (conduction and infiltration) anesthesia after a complete clinical and radiological examination, cutting out and peeling off the mucoperiosteal flap, followed by trepanation of the bone to visualize the apical part of the roots, curettage, resection of the root apices by 3 mm with a turbine tip and a bur, followed by control of the cut surface of the root stump with a solution methylene blue to detect additional calcified canals, forming a cavity 3 mm deep along the canal axis with an ultrasonic tip and attachment for subsequent retrograde filling and drying it, followed by retrograde obturation with ProRoot MTA material and its compaction with a microplugger, returning the mucoperiosteal flap to its place, suturing the wound and performing targeted intraoral radiography.

The disadvantage of the known technical solution is the depth of instrumental treatment of the tooth canal of only 3 mm, which, in the case of a missed canal, is insufficient for its adequate instrumental and medicinal treatment.

The task, which the claimed method is aimed at solving, is to increase the depth of retrograde instrumental processing of the root canal of the tooth while preserving the dentin of the root of the tooth, reduce the amount of microflora and remove non-hermetic obturation material in its root canal, prepare an optimal shape of the root canal for subsequent irrigation and retrograde obturation, restore the periapical defect of bone tissue, preserve the functional and anatomical state of the tooth as an organ of the dentoalveolar system, and improve the patient's quality of life.

The technical result of the claimed technical solution is the prevention of complications associated with the persistence of the inflammatory process and its progression.

The problem is solved by the fact that the method of retrograde endodontic treatment of tooth root canals in the treatment of chronic apical periodontitis contains a complete clinical and radiographic examination, local anesthesia, performing a root apex resection operation, including mucosal incisions in the projection of the causative tooth, cutting out and peeling off the mucoperiosteal flap, bone trepanation until the apical part of the roots is visualized, curettage of pathologically altered tissues in the area of the tooth root apex followed by resection of the root apex by 3 mm from the apex, revision of the cut surface of the tooth root stump using a 1% methylene blue solution, formation of a 3 mm deep cavity along the canal axis using an ultrasonic tip and a retrograde preparation attachment, retrograde obturation using ProRoot MTA material and its compaction, repositioning of the mucoperiosteal flap into place and suturing it, while after by detaching the mucoperiosteal flap by trepanation of the bone, an osteotomic access is created in the outer cortical plate of the jaw in the projection of the root apex of the causal tooth, and after curettage, hemostasis is performed using collagen and adrenergic agents, with the resection of the root apex being carried out at an angle of 45 degrees to the root axis, with a bevel facing the vestibular surface, and a pre-curved rotary nickel-titanium file RaCe Evo made of controlled shape memory alloy (CMwire), fixed in an endodontic tip, is inserted retrogradely into the 3 mm deep cavity formed using an ultrasonic tip for retrograde preparation. Then, by advancing it into the middle and orifice parts of the canal, they are retrogradely instrumented with further formation of the root canal by sequentially using nickel-titanium files made of controlled shape memory alloy (CMwire), using instruments from smaller to larger sizes, after which retrograde instrumental treatment is performed in order to clean the walls of the root canal from the apical part to the orifice with reciprocating movements of the endodontic instrument XP-endo Finisher file made of M-Wire alloy for 2 minutes, followed by retrograde irrigation of the formed root canal from the apical part to the orifice part using an endodontic syringe filled with a 0.5% solution of chlorhexidine bigluconate, the root canal is dried retrogradely with sterile paper pins and a bioceramic sealer is retrogradely introduced into the lumen of the prepared root canal from the apical part to the orifice part using a rotary nickel-titanium file in in reverse mode with subsequent retrograde cleaning of the apical part of the root canal within 3 mm from the previously introduced sealer, after which retrograde obturation of the apical part of the root canal within 3 mm is carried out with a filling material of Portland cement, condensing it with a microplugger for retrograde obturation, excess filling material is removed from the cut surface of the tooth root stump, while all treatment is carried out using a dental operating microscope and radiovisiographic examination for its control.

The features that distinguish this technical solution from the prototype have not been found in known analogues.

The invention is illustrated with graphic materials.

Fig. 1 shows a targeted intraoral radiovisiographic image of tooth 1.4 before the root apex resection operation.

Fig. 2 shows a coronal (left) and sagittal (right) reformat of a computerized cone beam tomographic examination of tooth 1.4 before the root apex resection operation.

Fig. 3 shows a photograph of the visualization of the apices of the buccal roots after creating an osteotomy access.

Fig. 4 shows a photograph of the resected surfaces of the buccal roots.

Fig. 5 shows a photograph of a revision of the cut surface of the buccal roots, stained using a 1% methylene blue solution.

Fig. 6 shows a photograph of a missed canal in the mesial-buccal root of tooth 1.4.

Fig. 7 shows a photograph of retrograde preparation with an ultrasonic tip for retrograde preparation of the apical part of the mesial-buccal root canal stump.

Fig. 8 shows a photograph of retrograde preparation of the mesial-buccal root canal of tooth 1.4 using a RaCe EVO 15.02 nickel-titanium file.

Fig. 9 shows a photograph of retrograde preparation of the mesial-buccal root canal of tooth 1.4 using a RaCe Evo 30.02 nickel-titanium file.

Fig. 10 shows a targeted intraoral radiovisiographic image with an XP-endo Finisher file retrogradely inserted into the mesial-buccal canal of tooth 1.4.

Fig. 11 shows a photograph of cleaning the walls of the mesial-buccal root canal with an XP-endo Finisher file inserted retrogradely.

Fig. 12 shows a photograph of retrograde obturation of the apical part of the mesial-buccal root canal with Portland cement.

Fig. 13 shows a photograph of the surface of the stumps of the resected buccal roots of tooth 1.4 with retrogradely obturated root canals.

Fig. 14 shows a targeted intraoral radiovisiographic image of tooth 1.4 with retrogradely obturated root canals during a root apex resection operation.

Fig. 15 shows a coronal (left) and sagittal (right) reformat of a computerized cone beam tomographic examination of tooth 1.4 6 months after root apex resection surgery.

Fig. 16 shows a targeted intraoral radiovisiographic image of tooth 1.4 6 months after root apex resection surgery.

The method of retrograde endodontic treatment of root canals of teeth in the treatment of chronic apical periodontitis is carried out as follows.

Based on the data of the preoperative computer tomographic examination, the individual parameters of the operated root of the causal tooth are analyzed, determining the thickness of the root dentin, the presence of a lumen of the missed canal, the location of the bends, the quality and location of the obturating material. Based on the prognostic anatomical data, a choice is made for the method of retrograde preparation.

Under local (conduction and infiltration) anesthesia, incisions are made in the mucous membrane in the projection of the causative tooth.

The mucoperiosteal flap is cut out and peeled off.

An osteotomic access is created in the outer cortical plate of the jaw in the projection of the root apex of the causal tooth using a water-cooled surgical bur.

Trepanation of the bone is performed until the apical part of the roots is visualized. Pathologically altered tissues in the form of granulations are noted in the apical part of the roots. They are curettaged using a curettage spoon.

Hemostasis is performed using collagen and adrenergic agents.

The apical part of the tooth root is determined.

Using a turbine tip and a diamond bur, a resection of the root apex is performed by 3 mm from the apex at an angle of 45 degrees to the axis of the tooth root with a bevel facing the vestibular surface, followed by revision of the cut surface of the tooth root stump to identify the lumen of the root canal using a 1% solution of methylene blue.

The lumen of the missed root canal is visualized on the section of the tooth root stump.

Using an ultrasonic tip and a retrograde preparation attachment with water cooling, a cavity is formed for subsequent retrograde filling with a depth of 3 mm along the canal axis, creating a direction for the passage of the middle and orifice parts of the root canal.

A pre-curved (e.g. using dental tweezers) rotary nickel-titanium file RaCe EVO (FKG Dentaire SA, La Chaux de Fonds, Switzerland) made of an alloy with controlled shape memory (CMwire) of the appropriate size, fixed in an endodontic tip, is introduced retrograde into the formed cavity by advancing it into the middle and orifice parts of the canal. The angle and radius of curvature are determined clinically based on the angle of inclination of the tooth root for optimal insertion of the file through osteotomy access into the root canal.

Using an endodontic ruler, measure the depth of file insertion from the apical cut of the root to the point of maximum advancement towards the mouth, thus establishing the working length of the preparation.

Next, they move on to retrograde expansion and formation of the root canal to the working length, consistently increasing the size of the files.

After the root canal is formed, retrograde instrumental treatment is performed to clean the walls of the root canal from the apical part to the orifice with reciprocating movements using the XP-endo Finisher endodontic instrument with a file made of M-Wire alloy for 2 minutes.

Retrograde irrigation of the formed root canal is performed from the apical part to the orifice part using an endodontic syringe filled with a 0.5% solution of chlorhexidine bigluconate. The root canal is dried retrogradely with sterile paper pins.

A bioceramic sealer is introduced retrogradely into the lumen of the prepared root canal from the apical part to the orifice part using a rotary nickel-titanium file in reverse mode.

The apical part of the root canal is cleaned retrogradely within 3 mm of the previously introduced sealer and dried.

Retrograde obturation of the apical part of the root canal is performed within 3 mm with a filling material of Portland cement (for example, ProRoot MTA), condensing it with a special instrument - a microplugger for retrograde obturation.

The excess is removed from the cut surface of the tooth stump using a dental trowel.

X-ray control of retrograde obturation of the root canal is carried out.

The mucoperiosteal flap is put back in place. The wound is sutured.

The treatment is carried out using optical magnification (dental operating microscope), which allows the dentist to achieve high accuracy in determining the root canals and other anatomical elements of the root canal structure on the section of the tooth root stump during the operation of root apex resection, followed by their closure with a retrograde filling, which eliminates the risk of complications, ensures high quality of retrograde obturation by conducting a radiovisiographic study to monitor the treatment.

Treatment using the proposed method and achieving the technical result is explained using a specific example of implementation.

Clinical example

Patient B., 37 years old, complained of discomfort in tooth 1.4.

History of the disease: endodontic treatment of tooth 1.4 was performed 3 years ago, the tooth is under an artificial crown. According to the patient, two months ago a dull pain appeared in the area of tooth 1.4, which intensified when biting.

Objectively: the crown of tooth 1.4 is restored with a metal-ceramic crown. The marginal fit of the crown is satisfactory. The mucous membrane of the transitional fold in the projection of the root tips is pale pink, not edematous, palpation is slightly painful. Percussion is sensitive. The probing depth of the circular groove is 2 mm. The reaction to thermal stimuli is negative.

Data from additional examination methods: on the targeted radiograph, the crown part of tooth 1.4 is restored with a metal-ceramic crown, the marginal fit is satisfactory.

The tooth cavity is filled with radiopaque material. The tooth has a three-root anatomical shape with two buccal and one palatal root. The palatal and distobuccal root canals are homogeneously obturated with radiopaque material, not reaching the radiographic apex by 1 mm. Inhomogeneous arrangement of radiopaque material is observed in the orifice of the mesial-buccal root canal. The lumen of the mesial-buccal root canal is free of radiopaque material in the middle and apical parts (Fig. 1).

On cone beam computed tomography, radiolucent bone destruction measuring 2×2 mm is determined in the periapical region of the mesial-buccal and distal-buccal roots (Fig. 2).

Clinical diagnosis. K04.5 - Chronic apical periodontitis of tooth 1.4.

Treatment

Local infiltration anesthesia is administered in the projection of the causal tooth. Horizontal and vertical mucosal incisions are made in the projection of the causal tooth. A full-layer mucoperiosteal flap is peeled off in the projection of the causal tooth.

By means of bone trepanation, an osteotomic access is created in the external cortical plate of the jaw in the projection of the root apex of the causative tooth using a water-cooled surgical burr (Fig. 3) until the apical part of the roots is visualized. Pathologically altered tissues in the form of granulations are noted in the apical part of the roots. They are curettaged using a curettage spoon.

Hemostasis is performed using collagen and adrenergic agents.

The apices of the buccal roots of the tooth are determined.

Using a turbine tip and a diamond bur, the root apices of the causal tooth are resected 3 mm from the apex at an angle of 45 degrees to the axis of the tooth root with a bevel facing the vestibular surface (Fig. 4).

The cut surface of the tooth root stump is inspected to identify the lumen of the missed root canal in the mesial-buccal root using a 1% methylene blue solution (Fig. 5).

The lumen of the missed root canal is visualized on the section of the stump of the mesial-buccal root of the tooth (Fig. 6).

Retrograde preparation of the apical part of the mesial-buccal root canal is performed along its axis to a depth of 3 mm from the cut of the root stump using ultrasonic attachments for retrograde preparation with water cooling, creating a cavity for the directed passage of the middle and orifice parts of the mesial-buccal root canal (Fig. 7).

A pre-curved rotary nickel-titanium file RaCe Evo (FKG Dentaire SA, La Chaux de Fonds, Switzerland) made of a controlled shape memory alloy (CMwire), size 15.02, fixed in an endodontic tip, is inserted retrograde into the previously formed cavity by advancing it into the middle and orifice parts of the canal (Fig. 8).

Using an endodontic ruler, measure the depth of file insertion from the apical cut of the root to the point of maximum advancement towards the mouth, thus establishing the working length of the preparation.

Retrograde expansion and formation of the root canal to the working length is performed by sequentially using nickel-titanium files made of controlled-memory alloy (CMwire) of sizes 20.02, 20.04, 25.04, 30.02 (Fig. 9).

Retrograde instrumental treatment of the root canal walls is performed to clean them from the apical to the orifice part to the working length with reciprocating movements of the endodontic instrument XP-endo Finisher with a file made of M-Wire alloy for 2 minutes (Fig. 10). The XP-endo Finisher file is inserted retrogradely into the treated root canal to the working length and its position is confirmed by means of a targeted radiovisiographic image (Fig. 11).

Retrograde irrigation of the formed root canal is performed from the apical part to the orifice part using an endodontic syringe filled with a 0.5% solution of chlorhexidine bigluconate. The root canal is dried retrogradely with sterile paper pins.

A bioceramic sealer is introduced retrogradely into the lumen of the prepared root canal from the apical part to the orifice part using a rotary nickel-titanium file in reverse mode.

The apical part of the root canal is cleaned retrogradely within 3 mm of the previously introduced sealer.

Retrograde obturation of the apical part of the root canal is performed within 3 mm with a filling material of Portland cement (for example, ProRoot MTA), condensing it with a special instrument - a microplugger for retrograde obturation (Fig. 12).

Excess filling material (Portland cement) is removed from the cut surface of the tooth stump (Fig. 13).

Retrograde preparation of the distobuccal root canal is performed using ultrasonic tips with water cooling to a depth of 3 mm along the root canal axis. The space of the retrogradely treated cavity is irrigated with a 0.5% solution of chlorhexidine bigluconate. The cavity is dried and retrograde obturation is performed with Portland cement (e.g., ProRoot MTA).

A radiographic check of the retrograde obturation of the root canals is performed, where homogeneously obturated canals of the mesial-buccal canal to the orifice part are determined, and of the distal-buccal root - in the apical part with radiopaque material (Fig. 14). The flap is placed in place and fixed with sutures.

All stages of treatment are carried out using optical magnification.

Dynamic observation after 6 months.

Examination: in the area of tooth 1.4, the mucous membrane of the gum is pink, not edematous, the gingival margin is normal. The sulcular part of the gum is located correctly in the area of the crown on tooth 1.4. Recession of the sulcular part of the gum and papillae is not determined.

Percussion of tooth 1.4 is painless.

The cone-beam computed tomogram shows homogeneous filling of the middle and apical parts of the root canal lumen of the mesial-buccal root with radiopaque filling material. The apical part of the distal-buccal root is filled with radiopaque material. Periapically, in the area of the buccal roots, restoration of bone tissue and the vestibular cortical plate is observed (Fig. 15).

On the target radiograph, homogeneously obturated canals of the mesial-buccal root up to the orifice part with radiopaque material are determined (Fig. 16).

Thus, this method allows instrumental cleaning of the root canal space to a depth of more than 3 mm, while preserving the dentin of the tooth root, forming the optimal shape of the root canal for irrigation and subsequent homogeneous obturation, preserving the functional and anatomical state of the tooth as an organ of the dental system, and improving the patient's quality of life.

This method of retrograde endodontic treatment of root canals of teeth can be used by both general dentists and dental surgeons in dental medical institutions.

Claims (1)

A method of retrograde endodontic treatment of tooth root canals in the treatment of chronic apical periodontitis, comprising a clinical and radiographic examination, local anesthesia, performing a root apex resection operation, including mucosal incisions in the projection of the causative tooth, cutting out and peeling off the mucoperiosteal flap, trepanning the bone until the apical part of the roots is visualized, curettage of pathologically altered tissues in the area of the tooth root apex followed by resection of the root apex by 3 mm from the apex, revision of the cut surface of the tooth root stump using a 1% methylene blue solution, formation of a 3 mm deep cavity along the canal axis using an ultrasonic tip and a retrograde preparation attachment, retrograde obturation using ProRoot MTA material and its compaction, repositioning the mucoperiosteal flap into place and suturing it, characterized in that after peeling off an osteotomy access is created in the outer cortical plate of the jaw in the projection of the root apex of the causal tooth using a mucoperiosteal flap by means of bone trepanation, and after curettage, hemostasis is performed using collagen and adrenergic agents, with the root apex resection being performed at an angle of 45 degrees to the root axis, with a bevel facing the vestibular surface, and a pre-curved rotary nickel-titanium file RaCe Evo made of an alloy with controlled shape memory (CMwire), fixed in an endodontic tip, is inserted retrogradely into the 3 mm deep cavity formed using an ultrasonic tip for retrograde preparation, and by advancing it into the middle and orifice parts of the canal, their retrograde instrumental processing is performed with further formation of the root canal by sequentially using nickel-titanium files made of an alloy with controlled shape memory (CMwire), using instruments from smaller to larger sizes, after which retrograde instrumental processing is performed in order to clean the walls root canal from the apical part to the orifice with reciprocating movements of the endodontic instrument XP-endo Finisher with a file made of M-Wire alloy for 2 minutes, followed by retrograde irrigation of the formed root canal from the apical part to the orifice part using an endodontic syringe filled with a 0.5% solution of chlorhexidine bigluconate, dry the root canal retrogradely with sterile paper pins and retrogradely introduce a bioceramic sealer into the lumen of the prepared root canal from the apical part to the orifice part using a rotary nickel-titanium file in reverse mode, followed by retrograde cleaning of the apical part of the root canal within 3 mm from the previously introduced sealer, after which retrograde obturation of the apical part of the root canal is performed within 3 mm with a filling material of Portland cement, condensing it with a microplugger for retrograde obturation, Excess filling material is removed from the cut surface of the tooth stump, and all treatment is carried out using a dental operating microscope and radiovisiographic examination for its control.