journal

Case Report Surgical Sealing of Laterally Localized Accessory with Resin Containing S-PRG Filler in Combination with Non-Surgical Endodontic Treatment: A Case Report

Shizu Hirata-Tsuchiya 1 , Shigeki Suzuki 1,2,* , Takashi Nakamoto 3 , Naoya Kakimoto 3, Satoru Yamada 2 and Hideki Shiba 1

1 Department of Biological , Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; [email protected] (S.H.-T.); [email protected] (H.S.) 2 Department of and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan; [email protected] 3 Department of Oral and Maxillofacial Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; [email protected] (T.N.); [email protected] (N.K.) * Correspondence: [email protected]

 Received: 6 October 2020; Accepted: 18 November 2020; Published: 20 November 2020 

Abstract: The spread of root canal infection to surrounding periodontal tissue through accessory root canals reduces the success rate of endodontic treatment. In this case, cone-beam computed tomography revealed a lesion (4 mm from the apex) resulting from an accessory root canal of the maxillary left central . First, non-surgical endodontic treatment was conducted but the sinus tract remained. Surgical preparation of the root cavity was then conducted to remove potentially infected surrounding the accessory root canal. The cavity was filled and the foramen was sealed with resin containing bioactive surface pre-reacted glass (S-PRG) filler. The photopolymerized resin was then contoured and polished. In combination with subsequent supportive non-surgical endodontic treatment, a good clinical outcome with the disappearance of the sinus tract and clinical symptoms such as discomfort and pressure pain and the regeneration of the alveolar bone hanging over the cavity was obtained. In this case, the good clinical outcome may have been due to the dentin-adhesive property and durability of the pre-adhesive system and composite resin. The better biocompatibility of S-PRG fillers presumably facilitated periodontal tissue healing.

Keywords: accessory canal; endodontic surgery; maxillary incisor

1. Introduction Dental and subsequent apical periodontitis are mainly caused by the carious and traumatic infection of dental tissue and endodontic treatment is needed to remove the invading oral bacteria. Successful treatment rates were found to be 92%, 74% and 88% for primary endodontic treatment and 86%, 67% and 89% for secondary endodontic treatment in the maxillary central incisor, maxillary secondary incisor and , respectively [1]. The presence of anatomical features such as root construction, root curving, ramifications and lateral root canals, which result in bacterial remnants and their products, is considered to reduce the success rate of endodontic treatment [2,3].

Dent. J. 2020, 8, 0131; doi:10.3390/dj8040131 www.mdpi.com/journal/dentistry Dent. J. 2020, 8, 0131 2 of 9

Almost all maxillary central possess a single root with a single canal although there are rare exceptions with two or four root canals [4–6]. In contrast to the limited variation in the number of root canals, it is well known that 62.2%, 49.1% and 41.9% of maxillary central incisors, maxillary secondary incisors and maxillary canines, respectively, possess accessory canals including ramifications [7]. Most of the accessory canals in these teeth are localized within 3 mm of the apex; therefore, clinicians usually trim within 3 mm of the root tip in the case of , thereby maintaining an appropriate to root ratio. However, 15.9%, 19.7% and 19.4% of maxillary central incisors, maxillary secondary incisors and canines, respectively, possess accessory canals more than 3 mm away from the apex [7]. Therefore, non-surgical endodontic treatments alone may not result in favorable clinical outcomes for maxillary incisors and canines when periodontal infection is caused by pathogens in such accessory canals. Mineral trioxide aggregate (MTA) is used for perforation repair because of its ability to induce tissue formation, thereby facilitating the formation of a physiological periodontal ligament-cementum structure [8]. However, because MTA does not possess a dentin-adhesive property, the cavity for MTA requires at least 3 4 mm thickness to prevent microleakage [9,10]. Moreover, − ethylenediaminetetraacetic acid (EDTA) is known to interfere with MTA hydration and consequently decreases the hardness and biocompatibility [11]. To the best of our knowledge, no clinical study has been conducted to evaluate the durability of MTA and the adhesive strength between MTA and dentin against the mechanical and chemical stress of endodontic treatment. Surface pre-reacted glass (S-PRG) fillers whose outer layer consists of glass ionomer cement secretes fluoride ions, sodium ions, borate ions, aluminum ions, silicate ions and strontium ions [12–18]. A prototype of S-PRG paste was able to induce mineral formation in vitro [12] and exhibited antioxidant [13] and antimicrobial [14,15] abilities. Furthermore, when compared with non-treated controls, the application of the prototype of S-PRG paste as an intracanal medication in a rat induced apical periodontitis model promoted periapical tissue healing equivalent to that promoted using Ca(OH)2 [16]. The higher ion releasing capacity of S-PRG contributes not only to the antimicrobial ability [14,15] but also to the cellular migrative properties of human gingival fibroblasts through activating an extracellular signal-regulated kinase 1/2 (ERK1/2) [17]. Therefore, recent accumulating evidence indicates the usefulness of S-PRG filler for surgical root sealing of the foramina of accessory root canals and perforation spots although the prototype of S-PRG paste lacked durability and a dentin-adhesive property. Resin containing S-PRG filler is widely used as restorative material of the crown partly due to its durability, dentin-adhesive property, antimicrobial ability and biocompatibility. However, its ability to fill the cavity adjacent to the area where periodontal tissue regeneration is expected such as the perforation spot and trimmed root surface in apicoectomy has not yet been elucidated. Here, we report a case in which non-surgical endodontic treatment followed by the surgical disinfection of accessory root canals and surrounding infected dentin by cavity preparation and by filling the cavity with resin containing S-PRG filler was performed for a lesion restricted in the middle part of the maxillary incisor. This suggested the importance of the decision to conduct a surgical procedure for endodontic treatment to fill the prepared accessory root with durability and biocompatibility to induce periodontal tissue healing and regeneration.

2. Case Report A female patient aged 18 years was referred to a private dental clinic for cosmetic problems caused by a black-colored left maxillary central incisor. As swelling in the attached gingiva surrounding the upper left maxillary incisor was observed, X-ray analysis was performed with and without the insertion of gutta-percha points (GC Dental Industrial Corp, Tokyo, Japan) in the sinus tract in order to identify the lesion area (Figure1A,B). Dent. J. 2020, 8, 0131 3 of 9 Dent. J. 2020, 8, x FOR PEER REVIEW 3 of 9

FigureFigure 1. 1. X-rayX-ray films films without without ( (AA)) and and with with ( (BB)) the the insertion insertion of of gutta-perch gutta-perchaa points points when when the the patient patient waswas 18 18 years years and and 8 8 months months old. old. These These X-rays X-rays were were ta takenken at at a a private private dental dental clinic clinic before before the the patient patient camecame to to our our university university dental dental hospital. hospital.

AsAs there there was was no no response response to to the the electric electric pulp pulp te testst in in the the affected affected , tooth, the the pulpal pulpal cavity cavity was was accessedaccessed andand standardstandard endodontic endodontic treatments treatments including including reaming, reaming, filing, rootfiling, irrigation root andirrigation application and ® ® applicationof a Ca(OH) of2 water-based a Ca(OH)2 pastewater-based (Calcipex paste II , Nippon(Calcipex Shika II , YakuhinNipponCo., Shika Ltd., Yakuhin Yamaguchi, Co., Japan)Ltd., Yamaguchi,were conducted Japan) three were times. conducted The patient three was times. then introducedThe patient to was Hiroshima then introduced University to Hospital Hiroshima and Universitythe above detailsHospital and and dental the above radiographs details (Figureand dental1A,B) radiographs were provided (Figure in the1A,B) response were provided letter from in the responsedentist at letter the private from the clinic dentist to our at the inquiry. private According clinic to our to the inquiry. history-taking According at to the the university history-taking hospital, at thewhen university the patient hospital, was around when the 10 yearspatient old, was the around toothdeveloped 10 years old, severe the tooth caries developed and was restored severe caries using andcomposite was restored resin at anotherusing composite private dental resin clinic. at anothe As ther patientprivate diddental not rememberclinic. As thethe name patient and did address not rememberof the dental the clinic name where and address this initial of the treatment dental clinic wasperformed, where this noinitial further treatment information was performed, on the initial no furthertreatment information was available. on the initial treatment was available. TheThe medical medical histories histories of of the the patient patient and and her her fa familymily were were non-contributory and and no no traumatic traumatic historyhistory of of the the frontal frontal teeth teeth was was revealed revealed by by history-taking. history-taking. At At the the time time of of the the first first examination examination at at the the universityuniversity hospital, hospital, swelling swelling was was observed observed and and the the left left maxillary maxillary incisor incisor was was discolored discolored (Figure 22A).A). SlightSlight pressure pressure pain pain and and notable notable fistulization fistulization were were identified identified in inthe the swollen swollen area. area. However, However, no spontaneousno spontaneous pain pain or significant or significant perpendicular perpendicular or horizontal or horizontal percussion percussion pain painwas identified. was identified. The probingThe probing depth depth of the of theleft leftmaxillary maxillary incisor incisor was was within within 2 mm 2 mm and and tooth tooth movement movement was was within within physiologicalphysiological limits; limits; thus, thus, root root fracture fracture was was not not assumed. assumed. The The palatal palatal side side was was sealed sealed with with hydraulic hydraulic cement.cement. Dental Dental radiographs radiographs taken taken at at the the first first visit visit to to the the university university hospital hospital as as well well as as radiographs radiographs providedprovided by the privateprivate dentaldental clinicclinic revealed revealed that that the the width width of of the the root root canal canal adjacent adjacent to theto the apex apex of theof theleft left maxillary maxillary incisor incisor was was narrower narrower than than that that of the of the maxillary maxillary right right central central incisor incisor (Figures (Figures1 and 1 2andB ). 2B).The The upper upper two-thirds two-thirds of theof the crown crow siden side were were filled filled with with Calcipex Calcipex II II®® from the the previous previous treatment. treatment. Moreover,Moreover, the width of the periodontal ligament sp spaceace was slightly enlarged (Figures1 1 and and2 B).2B). TheThe maxillarymaxillary leftleft central central incisor incisor was was isolated isolat withed awith rubber a dam.rubber Standard dam. Standard endodontic endodontic treatments treatmentsincluding the including measurement the measurement of the root canal of the length root ca bynal electronic length by apex electronic locator, reaming,apex locator, filing reaming, and root filingirrigation and root were irrigation conducted. were An conducted. electron apex An locator electron indicated apex locator an orifice indicated of the an lateral orifice accessory of the lateral canal accessoryat the middle canal of at the the root middle because of the the root working because length the atworking which thelength meter at which indicated the themeter apex indicated was shorter the apexthan was expected. shorter A than slight expected. exudate infiltratedA slight exudate on the paperinfiltrated point on when the itpaper reached point the when orifice it ofreached the lateral the orificeaccessory of canalthe lateral through accessory the main canal root canal.through The the patient main felt root pain canal. when endodonticThe patient files felt were pain inserted when endodonticover the orifice files ofwere the inserted lateral accessory over the canal.orifice of the lateral accessory canal.

Dent. J. 2020, 8, 0131 4 of 9 Dent. J. 2020, 8, x FOR PEER REVIEW 4 of 9

Dent. J. 2020, 8, x FOR PEER REVIEW 4 of 9

FigureFigure 2. 2. PreoperativePreoperative intraoral intraoral photograph photograph ( (AA)) and and dental dental radiophotograph radiophotograph ( (B).). Figure 2. Preoperative intraoral photograph (A) and dental radiophotograph (B). Cone-beamCone-beam computed computed tomography tomography (CBCT) (CBCT) demonst demonstratedrated a a horizontal horizontal accessory accessory canal canal at at the labiallabial side sideCone-beam of of the the root rootcomputed in inthe the sagittal tomography sagittal section section (CBCT) (Figure (Figure demonst 3A,3 arrow),A, arrow),rated bone a horizontal bone resorption resorption accessory (length (length =canal 6 mm, =at 6widththe mm, labial side of the root in the sagittal section (Figure 3A, arrow), bone resorption (length = 6 mm, width =width 5.5 mm)= 5.5 whose mm) whose center center was positioned was positioned at the at theforamen foramen of ofthe the horizontal horizontal accessory accessory canal canal on on the the = 5.5 mm) whose center was positioned at the foramen of the horizontal accessory canal on the horizontalhorizontal section section (Figure (Figure 33B,B, arrow)arrow) andand locallocal enlargementenlargement ofof thethe periodontalperiodontal ligamentligament spacespace onon thethe horizontal section (Figure 3B, arrow) and local enlargement of the periodontal ligament space on the mesialmesial side side of of the the middle middle part part of of the the root root (Figure (Figure 3C).3C). In In contrast contrast to tothe the labial labial and and medial medial sides sides of the of mesial side of the middle part of the root (Figure 3C). In contrast to the labial and medial sides of the middlethe middle part part of the of theroot, root, the the bone bone surrounding surrounding the the apical apical apex apex was was not not resorbed resorbed and and labial labial bone middle part of the root, the bone surrounding the apical apex was not resorbed and labial bone resorption did not reach the apical apex (Figure 3A,C). A schematic view of the periapical region resorptionresorption did did not not reach reach the the apical apical apex apex (Figure (Figure3A,C). 3A,C). A schematic A schematic view view of the of periapicalthe periapical region region based based on CBCT analyses showed 4.0 mm and 2.0 mm distances from the anatomical apex to the orifice onbased CBCT on analyses CBCT analyses showed showed 4.0 mm 4.0 and mm 2.0 and mm 2.0 distances mm distances from from the anatomical the anatomical apex apex to the to orificethe orifice of the oflaterally ofthe the laterally laterally localized localized localized accessory accessory accessory root canal rootroot and canalcanal from and the from foramen thethe foramenforamen to the orificeto to the the oforifice orifice the laterallyof of the the laterally localizedlaterally localizedaccessorylocalized accessory root accessory canal, root root respectively; canal, canal, respectively; respectively; the angle thethe between angle between thebetween main the the root main main canal root root and canal canal the and laterally and the the laterally localizedlaterally localizedaccessorylocalized accessory root accessory canal root wasroot canal 85canal◦, whichwas was 85°, 85°, verified which which that verifiedverified the laterally thatthat thethe laterally localizedlaterally localized localized accessory accessory accessory root canal root root occurred canal canal occurrednaturallyoccurred naturally rather naturally than rather rather being than than caused being being by caused caused an iatrogenic byby an iatrogenic perforation perforation perforation (Figure3 (FigureD). (Figure 3D). 3D).

FigureFigure 3. 3.Preoperative Preoperative cone-beam cone-beam computedcomputed tomography tomography images images (A (A) sagittal,) sagittal, (B ()B horizontal) horizontal and and (C) (C) Figurecoronal.coronal. 3. ThePreoperative The arrow arrow in in (cone-beam A(A)) indicates indicates computed thethe laterallateral tomography foramen. (D (D images) )Schematic Schematic (A) viewsagittal, view ofof the (B the) sagittal horizontal sagittal section section and of ( C of) coronal.thethe upper upper The left left arrow incisor. incisor. in ( A) indicates the lateral foramen. (D) Schematic view of the sagittal section of the upper left incisor. TheThe above above findings findings suggested suggested that that inflammation inflammation spread spread into into the the periodontal periodontal ligament ligament tissue tissue from thefrom horizontalThe the above horizontal accessory findings accessory canalsuggested but canal not that but from inflammationnot the from apical the apexapicalspread and apex into this and the case thisperiodontal was case diagnosed was ligamentdiagnosed as laterally tissue as fromlaterally the horizontal localized inflammationaccessory canal caused but bynot infection from the of apical the accessory apex and root this canal. case Therefore, was diagnosed due to as laterally localized inflammation caused by infection of the accessory root canal. Therefore, due to

Dent. J. 2020, 8, 0131 5 of 9 localized inflammation caused by infection of the accessory root canal. Therefore, due to continuous Dent. J. 2020, 8, x FOR PEER REVIEW 5 of 9 exudate from the accessory root canal, we considered it prudent to discontinue the non-surgical endodonticcontinuous treatment exudate from and proposedthe accessory exploratory root canal, surgery we considered to the patient it prudent in order to discontinue to directly the examine non- andsurgical disinfect endodontic the lateral treatment accessory and canal proposed under explorat a microscope.ory surgery We obtained to the patient informed in order consent to directly from her andexamine her mother. and disinfect the lateral accessory canal under a microscope. We obtained informed consent fromAt her the and time her of mother. the surgery, local anesthesia was administered, the target side was opened and granulationAt the tissue time of was the removed. surgery, local The foramenanesthesia of was the administered, accessory canal the wastarget identified side was byopened microscopy and (Figuregranulation4A, arrowhead) tissue was and removed. the dentin The tissue foramen surrounding of the accessory the foramen canalwas was drilled identified out usingby microscopy a diamond bur(Figure of 0.5 mm4A, arrowhead) in diameter and to remove the dentin potentially tissue su infectedrrounding surrounding the foramen dentin was (Figuredrilled 4outB). using After thea cavitydiamond was disinfected bur of 0.5 mm with in 10% diameter sodium to hypochloriteremove potentially (NeoCleaner infected® ,surrounding Neo Seiyaku, dentin Nagoya, (Figure Japan) 4B). and washedAfter the with cavity saline, was a No.disinfected 25 K-file with was 10% inserted sodium into hypochlorite the main canal (NeoCleaner in order®,to Neo prevent Seiyaku, resin Nagoya, material fromJapan) leaking and intowashed the with main saline, canal, a thereby No. 25 K-file preventing was inserted subsequent into the non-surgical main canal endodontic in order to prevent treatment. Subsequently,resin material the from cavity leaking was treated into usingthe main a self-etching canal, thereby dentin-adhesive preventing system subsequent (Clearfil non-surgical MegaBond ®, Kurarayendodontic Medical, treatment. Okayama, Subsequently, Japan) and the filled cavity with was resin treated (Beautifil using flowa self-etching F02®, Shofu, dentin-adhesive Kyoto, Japan) ® (Figuresystem4C). (Clearfil Twelve MegaBond days after the, Kuraray surgery, Medical, no swelling Okayama, or clinical Japan) symptoms and filled werewith resin observed, (Beautifil the sutures flow F02®, Shofu, Kyoto, Japan) (Figure 4C). Twelve days after the surgery, no swelling or clinical were removed and the affected area was irrigated with saline. symptoms were observed, the sutures were removed and the affected area was irrigated with saline. Over the next 40 days, supportive non-surgical endodontic treatment was conducted five times. Over the next 40 days, supportive non-surgical endodontic treatment was conducted five times. At this stage, the root canal length was successfully measured and a working length of 25.0 mm from At this stage, the root canal length was successfully measured and a working length of 25.0 mm from the top of the crown was set. The apex was enlarged until No. 55 with a K-file and the prepared root the top of the crown was set. The apex was enlarged until No. 55 with a K-file and the prepared root canal was irrigated with 3% EDTA solution (Smearclean®, Nippon Shika Yakuhin Co., Ltd., Yamaguchi, canal was irrigated with 3% EDTA solution (Smearclean®, Nippon Shika Yakuhin Co., Ltd., ® Japan).Yamaguchi, Calcipex Japan). II Calcipexwas used II® as was a drugused as for a drug the root for the canal root and canal glass and polyalkenoateglass polyalkenoate cement cement (Base ® Cement(Base Cement, Shofu,®, Kyoto,Shofu, Kyoto, Japan) Japan) was used was as used a temporary as a tempor sealing.ary sealing. The fitness The fitness of the of gutta-percha the gutta-percha points (GCpoints Dental (GC Industrial Dental Industrial Corp, Tokyo, Corp, Japan) Tokyo, in Japan) the apex in the region apex wasregion examined was examined (Figure (Figure4D) and 4D) then and the rootthen was the filled root by was the filled lateral by condensation the lateral condensati method usingon method Grossman’s using rootGrossman’s canal sealer root (Nishikacanal sealer Canal ® Sealer(Nishika Eugenol Canal Quick Sealer E-Q Eugenol, Nippon Quick Shika E-Q Yakuhin®, Nippon Co., Shika Ltd., Yakuhin Yamaguchi, Co., Ltd., Japan) Yamaguchi, (Figure4E). Japan) (Figure 4E).

FigureFigure 4. 4.Operative Operative photographs photographs afterafter granulargranular tissue removal removal (A), (A), after after cavity cavity preparation preparation (B) ( Band) and afterafter sealing sealing with with composite composite resin resin ( C(C).). The The arrowheadarrowhead in ( (AA)) indicates indicates the the lateral lateral foramen. foramen. X-ray X-ray films films beforebefore (D ()D and) and after after (E ()E root) root filling. filling. The The fitnessfitness ofof gutta-perchagutta-percha points points in in the the apex apex was was examined examined (D ().D ).

Dent. J. 2020, 8, 0131 6 of 9

Dent.Fourteen J. 2020, 8, daysx FORafter PEER rootREVIEW canal obturation, the accessible palatal cavity was filled with the composite6 of 9 resin for a permanent restoration. Three months, one year and two years after root canal obturation, Fourteen days after root canal obturation, the accessible palatal cavity was filled with the CBCT analyses were performed. The lateral canal remained closed by the filled resin material even after composite resin for a permanent restoration. Three months, one year and two years after root canal two years and the absence of labial bone resorption was chronologically confirmed on cross, sagittal obturation, CBCT analyses were performed. The lateral canal remained closed by the filled and horizontal sections (Figure5). Furthermore, no recurrence of gingival swelling was confirmed on resin mater photographs and no clinical symptoms were observed.

FigureFigure 5. 5.Cone-beam Cone-beam computed computed tomography tomography images images at at three three months months (A (A) sagittal,) sagittal, ( B(B)) horizontal horizontal and and ( C) coronal;(C) coronal; one year one (D year) sagittal, (D) sagittal, (E) horizontal (E) horizontal and (F) and coronal (F) coronal and two and years two (G years) sagittal, (G) (sagittal,H) horizontal (H) andhorizontal (I) coronal and after (I) coronal root filling. after root filling.

3. Discussion3. Discussion AsAs described described above, above, 62.2% 62.2% ofof maxillarymaxillary centralcentral incisors have have access access to to periodontal periodontal ligament ligament tissuetissue other other than than the the apex apex foramen foramen [ 1[1].]. However,However, apical periodontitis periodontitis mostly mostly spreads spreads from from the the apex, apex, presumablypresumably because because the the diameter diameter ofof thethe apexapex foramenforamen is larger larger than than that that of of the the lateral lateral foramen foramen and and ramificationsramifications [19 [19,20].,20]. Moreover, Moreover, pulp pulp tissue tissue inin accessoryaccessory canals canals may may survive survive and and be be immunologically immunologically resistant to bacterial invasion from the main root canal even when apical periodontitis with a resistant to bacterial invasion from the main root canal even when apical periodontitis with a radiolucent radiolucent area is noted [20]. The average diameter of the main in the maxillary area is noted [20]. The average diameter of the main apical foramen in the maxillary frontal teeth frontal teeth is 0.28 mm according to Chapman et al. [21] and 0.31 mm according to Abdullah et al. is 0.28 mm according to Chapman et al. [21] and 0.31 mm according to Abdullah et al. [22]. Indeed, [22]. Indeed, the apical foramen was narrow (Figures 1 and 2) and a thin dentin bridge-like the apical foramen was narrow (Figures1 and2) and a thin dentin bridge-like radiopaque white radiopaque white line was identified at the horizontal level of the lateral root foramen by CBCT lineanalysis was identified (Figure 3). at Thus, the horizontal we hypothesized level of that the the lateral pulp roottissue foramen in the apical by CBCT region analysis had calcification (Figure3 ). Thus,ability. we hypothesizedAs prolonged pulpthat theinflammation pulp tissue is inknown the apical to be regionrelated hadto pulp calcification calcification ability. such Asas the prolonged pulp pulpstone inflammation [23] we assumed is known that to the be bacterial related to remnants pulp calcification from the primary such as thecarious pulp treatment stone [23 ]received we assumed at thataround the bacterial 10 years remnantsof age induced from chronic the primary pulpal inflammation, carious treatment which received may have at caused around the 10 calcification years of age inducedin the chronicapical region. pulpal As inflammation, we were unable which to feel may any have dentin caused bridge-like the calcification hard tissue in by the hand apical during region. Asnon-surgical we were unable endodontic to feel anytreatment, dentin this bridge-like hard tissue hard was tissue suggested by hand to be during fragile non-surgical and flimsy. endodontic treatment,The thissuccessful hard tissue prognosis was suggestedrates of apicoectomy to be fragile by andtraditional flimsy. surgery and microsurgery are 59% and 94%, respectively [24]. The main advantages of the microscopic view during the apicoectomy procedure are that it is easy to identify non-treated root canals and microcracks on the root surface Dent. J. 2020, 8, 0131 7 of 9

The successful prognosis rates of apicoectomy by traditional surgery and microsurgery are 59% and 94%, respectively [24]. The main advantages of the microscopic view during the apicoectomy procedure are that it is easy to identify non-treated root canals and microcracks on the root surface as well as the cut surface. After trimming the root tip, clinicians tend to concentrate on the cut surface; however, clinicians should also explore the remaining foramens of lateral accessory root canals even on the palatal/lingual side. From the point of view of the crown/root ratio influence on the tooth lifespan, the remaining foramen should be sealed rather than undergoing further trimming of the root tip. Non-surgical treatment was conducted to mechanically and chemically disinfect the main root canal. However, the clinical symptoms and signs did not improve necessitating the need for surgical treatment. A slight exudate infiltrated the paper point only when it reached the orifice of the lateral accessory canal through the main root canal. Therefore, the root canal infection was mainly due to communication with the periodontal area surrounding the foramen of the laterally localized accessory root canal and infection of the accessory root canal and the surrounding dentin. It is widely accepted that surgical treatment should be conducted only when non-surgical endodontic treatment has failed. In the present case, our decision for surgical treatment might be considered to have been early. We were unable to wait for a tissue healing response under non-surgical treatment due to the limited period of hospital attendance. MTA, composite resin, glass polyalkenoate cement and o-ethoxybenzoic acid cement (EBA cement) are the alternative choices for filling materials of perforation spots. Among these materials, MTA is widely accepted as the best from a periodontal tissue regeneration point of view. However, MTA requires 3 4 mm of thickness to block microleakage [9,10]. In the present − case, the horizontal accessory canal had a length of 2 mm at the labial side of the root in the sagittal section (Figure3); therefore, in order to prevent detachment of the filling material during subsequent supportive mechanical and chemical endodontic treatments, the self-etching dentin-adhesive system and composite resin were selected based on their strong adhesive strength and chemical stability. The composite resin (Beautifil Flow F02®, Shofu) used in this case contains an S-PRG filler and is categorized as a giomer [25]. When the coronally positioned flap operation was conducted to restore gingival recession, the gingival epithelium was re-attached to the GIOMER surface to construct a long junctional epithelium and the root coverage rate of the GIOMER surface was higher than that of glass ionomer cement and GIOMER-free composite resin surfaces [26]. Thus, the relatively higher biocompatibility of the GIOMER may have reduced the radiolucent area and regenerated alveolar bone tissue even in the area hanging over the resin at one and two years after the surgery (Figure5D–I). MTA has been applied to seal perforations in roots and the bottom of the pulp chamber with a good prognosis, without inducing periodontal tissue inflammation in clinical settings and in in vivo experimental animal models [27,28]. According to a meta-analysis of the treatment outcome of repaired root perforations [29], an overall success rate of 72.5% was estimated for non-surgical repair of root perforations and the rate increased to 80.9% only when MTA application cases were included. In a long-term evaluation of the repair of root perforations with MTA application [30], which was one of the clinical analyses used in the reported meta-analysis [29], teeth were classified into a ‘healing’ group if only two or less of the five clinical and radiographic findings, namely, radiolucency adjacent to the perforation site, continuing root resorption, clinical signs, clinical symptoms and loss of function, were identified at the time of evaluation. If we apply this rule in the present case, radiolucency was adjacent to the perforation site, clinical signs (the presence of sinus tract) and clinical symptoms (discomfort and pressure pain) were identified and only radiolucency adjacent to the perforation site was identified at pre- and postoperative stages (both post one and two years). These scoring results implied that the lesion was healed. Therefore, by considering the reduced radiolucent area at post one and two years, the resin containing S-PRG filler used in the present case can be regarded to possess an apparent regenerative ability equivalent to MTA cements. The possibility of minor leakage between dentin and MTA cement or MTA dropout due to mechanical and chemical stress was not excluded before treatment. Therefore, in addition to the application of MTA only being authorized for Dent. J. 2020, 8, 0131 8 of 9 treatment (not for perforation repair) under the Japanese health insurance system, we selected resin containing S-PRG filler as the filling material in this case.

4. Conclusions This case report strongly recommends dentists to consider the existence of accessory root canals while conducting endodontic treatment of maxillary incisors. As there are several advantages to performing surgical endodontic treatment for maxillary incisors including easy access to the lesion area with minimum bone fenestration due to the thin labial cortical bone and ease in securing the operative field, surgery should be considered if the primary non-surgical treatment fails to cure the laterally localized accessory root canal. Resin containing S-PRG filler should be an ideal sealing material for the cases without securing sufficient material thickness, considering its regenerative capability, adhesive properties and durability.

Author Contributions: Conceptualization, S.S.; Data curation, S.S. and S.H.-T.; Formal Analysis, T.N. and N.K.; Investigation, S.S. and S.H.-T.; Writing—Original Draft Preparation, S.S.; Writing—Review and Editing, S.S.; Visualization, S.H.-T.; Supervision, S.Y. and H.S.; Project Administration, S.S. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Acknowledgments: We thank Kazuo Yamauchi for providing us with the medical history and for the two dental radiographs that are presented in Figure1. Conflicts of Interest: The authors declare no conflict of interest.

References

1. Sjogren, U.; Hagglund, B.; Sundqvist, G.; Wing, K.J. Factors affecting the long-term results of endodontic treatment. J. Endod. 1990, 16, 498–504. [CrossRef] 2. Cunningham, C.J.; Senia, E.S. A three-dimensional study of canal curvatures in the mesial roots of mandibular molars. J. Endod. 1992, 18, 294–300. [CrossRef] 3. Siqueira, J.F., Jr.; Araújo, M.C.; Garcia, P.F.; Fraga, R.C.; Dantas, C.J. Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. J. Endod. 1997, 23, 499–502. [CrossRef] 4. Sponchiado, E.C., Jr.; Ismail, H.A.; Braga, M.R.; de Carvalho, F.K.; Simões, C.A. Maxillary central incisor with two root canals: A case report. J. Endod. 2006, 32, 1002–1004. [CrossRef][PubMed] 5. Rahimi, S.; Shahi, S.; Yavari, H.R.; Reyhani, M.F.; Ebrahimi, M.E.; Rajabi, E. A stereomicroscopy study of root apices of human maxillary central incisors and mandibular second in an Iranian population. J. Oral Sci. 2009, 51, 411–415. [CrossRef][PubMed] 6. Aznar Portoles, C.; Moinzadeh, A.T.; Shemesh, H. A central incisor with 4 independent root canals: A case report. J. Endod. 2015, 41, 1903–1906. [CrossRef][PubMed] 7. Adorno, C.G.; Yoshioka, T.; Suda, H. Incidence of accessory canals in Japanese anterior maxillary teeth following root canal filling ex vivo. Int. Endod. J. 2010, 43, 370–376. [CrossRef] 8. Yildirim, T.; Genço˘glu,N.; Firat, I.; Perk, C.; Guzel, O. Histologic study of furcation perforations treated with

MTA or Super EBA in dogs0 teeth. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2005, 100, 120–124. [CrossRef] 9. Lamb, E.L.; Loushine, R.J.; Weller, R.N.; Kimbrough, W.F.; Pashley, D.H. Effect of root resection on the apical sealing ability of mineral trioxide aggregate. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2003, 95, 732–735. [CrossRef] 10. Valois, C.R.; Costa, E.D., Jr. Influence of the thickness of mineral trioxide aggregate on sealing ability of root-end fillings in vitro. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2004, 97, 108–111. [CrossRef] 11. Lee, Y.L.; Lin, F.H.; Wang, W.H.; Ritchie, H.H.; Lan, W.H.; Lin, C.P. Effect of EDTA on the hydration mechanism of mineral trioxide aggregate. J. Dent. Res. 2007, 86, 534–538. [CrossRef][PubMed] 12. Ito, S.; Iijima, M.; Hashimoto, M.; Tsukamoto, N.; Mizoguchi, I.; Saito, T. Effects of surface pre-reacted glass-ionomer fillers on mineral induction by phosphoprotein. J. Dent. 2011, 39, 72–79. [CrossRef][PubMed] Dent. J. 2020, 8, 0131 9 of 9

13. Ilyas, A.; Odatsu, T.; Shah, A.; Monte, F.; Kim, H.K.; Kramer, P.; Aswath, P.B.; Varanasi, V.G. Amorphous silica: A new antioxidant role for rapid critical-sized bone defect healing. Adv. Healthc. Mater. 2016, 5, 2199–2213. [CrossRef][PubMed] 14. Yassen, G.H.; Huang, R.; Al-Zain, A.; Yoshida, T.; Gregory, R.L.; Platt, J.A. Evaluation of selected properties of a new root repair cement containing surface pre-reacted glass ionomer fillers. Clin. Oral Investig. 2016, 20, 2139–2148. [CrossRef][PubMed] 15. Miki, S.; Kitagawa, H.; Kitagawa, R.; Kiba, W.; Hayashi, M.; Imazato, S. Antibacterial activity of resin composites containing surface pre-reacted glass-ionomer (S-PRG) filler. Dent. Mater. 2016, 32, 1095–1102. [CrossRef] 16. Xiong, B.; Shirai, K.; Matsumoto, K.; Abiko, Y.; Furuichi, Y. The potential of surface pre-reacted glass root canal dressing for treating apical periodontitis in rats. Int. Endod. J. 2020, in press. [CrossRef] 17. Yamaguchi-Ueda, K.; Akazawa, Y.; Kawarabayashi, K.; Sugimoto, A.; Nakagawa, H.; Miyazaki, A.; Kurogoushi, R.; Iwata, K.; Kitamura, T.; Yamada, A.; et al. Combination of ions promotes cell migration via extracellular signal-regulated kinase 1/2 signaling pathway in human gingival fibroblasts. Mol. Med. Rep. 2019, 19, 5039–5045. [CrossRef][PubMed] 18. Shimizubata, M.; Inokoshi, M.; Wada, T.; Takahashi, R.; Uo, M.; Minakuchi, S. Basic properties of novel S-PRG filler-containing cement. Dent. Mater. J. 2020, in press. [CrossRef][PubMed] 19. Ponce, E.H.; Fernández, J.A.V. The cemento-dentino-canal junction, the apical foramen, and the apical constriction: Evaluation by optical microscopy. J. Endod. 2003, 29, 214–219. [CrossRef][PubMed] 20. Ricucci, D.; Siqueira, J.F., Jr. Fate of the tissue in lateral canals and apical ramifications in response to pathologic conditions and treatment procedures. J. Endod. 2010, 36, 1–15. [CrossRef] 21. Chapman, C.E. A microscopic study of the apical region of human anterior teeth. J. Br. Endod. Soc. 1969, 3, 52–58. [CrossRef][PubMed] 22. Abdullah, D.A.; Kanagasingam, S.; Luke, D.A. Frequency, size and location of apical and lateral foramina in anterior . Sains Malays. 2013, 42, 81–84. 23. Giuroiu, C.L.; Căruntu, I.D.; Lozneanu, L.; Melian, A.; Vataman,M.; Andrian, S. Dental pulp: Correspondences and contradictions between clinical and histological diagnosis. BioMed Res. Int. 2015, 960321. [CrossRef] [PubMed] 24. Setzer, F.C.; Shah, S.B.; Kohli, M.R.; Karabucak, B.; Kim, S. Outcome of endodontic surgery: A meta-analysis of the literature–part 1: Comparison of traditional root-end surgery and endodontic microsurgery. J. Endod. 2010, 36, 1757–1765. [CrossRef][PubMed] 25. Ikemura, K.; Tay, F.R.; Endo, T.; Pashley, D.H. A review of chemical-approach and ultramorphological studies on the development of fluoride-releasing dental adhesives comprising new pre-reacted glass ionomer (PRG) fillers. Dent. Mater. J. 2008, 27, 315–339. [CrossRef][PubMed] 26. Sharma, V.; Sharma, M.; Singh, P.; Saxena, H.; Sharma, V.; Sharma, S.; Pant, V.A. Cervical restoration and the amount of soft tissue coverage achieved by coronally advanced flap. J. Adv. Med Dent. Sci. Res. 2019, 7, 65–69. 27. Juárez Broon, N.; Bramante, C.M.; de Assis, G.F.; Bortoluzzi, E.A.; Bernardineli, N.; de Moraes, I.G.; Garcia, R.B. Healing of root perforations treated with Mineral Trioxide Aggregate (MTA) and Portland cement. J. Appl. Oral Sci. 2006, 14, 305–311. [CrossRef] 28. Unal, G.C.; Maden, M.; Isidan, T. Repair of furcal iatrogenic perforation with mineral trioxide aggregate: Two years follow-up of two cases. Eur. J. Dent. 2010, 4, 475–481. [CrossRef] 29. Siew, K.; Lee, A.H.; Cheung, G.S. Treatment outcome of repaired root perforation: A systematic review and meta-analysis. J. Endod. 2015, 41, 1795–1804. [CrossRef] 30. Mente, J.; Leo, M.; Panagidis, D.; Saure, D.; Pfefferle, T. Treatment outcome of mineral trioxide aggregate: Repair of root perforations-long-term results. J. Endod. 2014, 40, 790–796. [CrossRef]

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