Disinfection of Gutta-Percha Cones Prior to Obturation: a Smattering of Historical Perspectives with a Focus on Contemporary Considerations

REVIEW ARTICLE

James L. Gutmann, Vivian Manjarrés Disinfection of gutta-percha cones prior to obturation: a smattering of historical perspectives with a focus on contemporary considerations

KEY WORDS antibiotics, atomic force microscopy, chlorhexidine, culturing, decontamination, disinfection, glutaraldehyde, gutta-percha, NaOCl

ABSTRACT The use of gutta-percha in dentistry and in particular root canal procedures has a long and tortu- ous history; its use has been the preferred obturation material of choice for well over a century, in spite of attempts to eliminate it for other entities that were erroneously perceived to be superior. However, because of the importance of asepsis and bacteriological control in the delivery of quality root canal procedures, the clinical disinfection of gutta-percha cones has arisen as a controver- sial issue as to its need and the use of the most effective agent for rapid chairside management. This review will touch upon a brief history of the material and subsequently delve into the issues surrounding the decontamination/disinfection of this material in the hope to establish the best evidence for the clinical choice of managing this challenge.

Introduction Royal Society of Arts, London, in 1843, for his con- tribution3. In 1845, Hancock and Bewley formed Gutta-percha comes from the trees of the genus the Gutta-Percha Company in the United King- Palaquium in the family Sapotaceae1, with the dom, and began to expand the uses of this material rigid natural latex produced from the sap of these over and above medical applications into a wide trees, in particular from Palaquium gutta. The variety of entities, with golf balls a prime product word gutta-percha is based on the plant’s name for over 50 years3. Its chemical structure has been in the Malayan Archipelago, getah perca, which is detailed in a number of publications that character- translated as ‘percha latex’. ise its composition along with its different phases of Gutta-percha was first used as a restorative ma- existence, primarily due to heat application3. terial, and now is considered as an essential part Edwin Truman is credited with introducing of obturation of the prepared root canal. First dis- gutta-percha into dentistry, with Asa Hill iden- covered by John Tradescant, who brought this tified in 1847 as developing ‘Hill’s-Stopping’, material after his travels to the Far East in 1656, a restorative material consisting of a mixture of he named this material ‘Mazer Wood’1. However, bleach, gutta-percha and carbonate of lime and introduction of this material into the medical field quartz that was patented in 18484. As reported was by Dr. William Montgomerie, a medical officer by Payne2, Hill indicated that this material, in his in the Indian service, who recognised the value of mind, was invaluable due to its “convenience, util- this material in 1822 when he was stationed in Sin- ity and harmlessness withal …”. gapore, but did not give the matter any attention Its use in root canals was first demonstrated by until 18422. He was awarded the gold medal by the Bowman in a dental meeting in St. Louis in 1867,

ENDO EPT 2019;13(3):191–206 191 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation

Table 1 Historical recommendations for gutta-percha decontamination

Recommendation Study (year) Substance Iodin (iodine) Crane8 (1920) Paraformaldehyde Nicholls9 (1967) Tincture of benzalkonium chloride Buchbinder10 (1966) Benzalkonium chloride solution Ingle11 (1965); Abramson and Norris12 (1966); Dowson and Garber13 (Zephiran) (1967); Nygaard-Ostby14 (1971); Doolittle et al15 (1975) Metaphen (Nitromersol) Torneck16 (1967); Grossman17 (1970); Schroeder18 (1981); Doolittle et al15 (1975) Alcohol Hall19 (1936); Healey20 (1960); Mumford21 (1966); Schroeder18 (1981); Doolittle et al15 (1975) Thimersol solution 0.19% Nicholls9 (1967) NaOCl Schroeder18 (1981) Propylene oxide gas Ehrmann et al22 (1975) Technique Immersion in solution Ingle11 (1965); Nicholls9 (1967); Dowson and Garber13 (1967); Torneck16 (1967); Grossman17 1970; Healey20 (1960); Sommer et al23 (1966); Schroeder18 (1981) Wiping or scrubbing Ingle11 (1965) Fuming Buchbinder10 (1966) Gaseous formocresol/vapours Doolittle et al15 (1975); Senia et al24 (1977)

where he provided direction in its use in the obtur- description of the material as used and a point is ation of the canals in an extracted first molar5. In merely a point, such as the period at the end of today’s world, gutta-percha, or gutta-perka, is this sentence.) the root canal filling material of choice. Need- Gutta-percha cones are approximately 20% less to say it has stood the test of time in treat- gutta-percha and 66% zinc oxide, along with ment and mistreatment. For many around the fillers, plasticisers and metal salts for colour and world, however, the pronunciation of the word radiographic contrast7. However, contemporarily, percha or perka has been a focus of attention, most compositions are proprietary in nature, with controversy and debate6. However, the lessons various studies having introduced antimicrobials of history prevail in this matter, as Dr. E.T. Payne into the gutta-percha in hopes to enhance its dis- clearly removed any misconceptions or ‘mistreat- infecting properties once placed in the shaped ments’ that we may have concerning this issue … root canal. However, the multitude of studies “It may be well to say right here that the proper that have attempted to define protocols for the pronunciation of the word is percha [ch sound as disinfection/decontamination of these cones are in chow] and not perka [k sound as in cat], as it fraught with an amazing array of variabilities is sometimes incorrectly called”2. Over 100 years and empiricisms, in addition to dealing with a later, International Standards were developed wide range of chemicals that may very well differ (ISO) for the approval of the specification of from country to country, continent to continent. root canal instruments and filling materials. The Hence, the most important and efficacious ques- American Dental Association Standard for the use tion that remains to be answered is what is the of gutta-percha cones in root canal obturation best way to maintain clinical asepsis in the use is No. 78. (Note – this review will use the term of any type of gutta-percha cone or core-carrier, ‘cone’ or ‘cones’ as opposed to ‘point’ or ‘points’ in a rapid, predictable chairside manner to meet to describe the shape of the gutta-percha used today’s demands within the provision of root canal for root canal obturation. While contemporarily procedures. both terms are used, the term ‘cone’ best fits the

192 ENDO EPT 2019;13(3):191–206 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation

Historical disinfection of gutta- substances and variable time frames have been percha in clinical usage investigated as to their ability to decontaminate gutta-percha cones, with the primary focus on the Disinfection of the root canal system is paramount use of sodium hypochlorite (NaOCl) since 197525. to success in root canal procedures. Likewise, the Substances that have been used in the decontam- disinfection or decontamination of any root canal ination/disinfection of gutta-percha cones include obturation materials would be essential if they can- the following: not be provided in a bacteria-free state or are anti- • NaOCl (0.5% to 6%) bacterial in nature. Furthermore, contamination • herbal solutions/preparations of these materials, such as gutta-percha, during • chlorhexidine 2% their use must be considered. Table 1 identifies • CaOCl2 the substances and techniques used historically in • alcohol (50% to 70%) the decontamination/disinfection of gutta-percha • Octenisept 0.05% (wound gel) (Schülke & cones. Mayr, Norderstedt, Germany) Beyond the guidance provided by the authors/ • povidone-iodine (PVP-I) 10% clinicians identified in Table 1, little evaluation of • BioPure MTAD (mixture of doxycycline, citric these methods of decontamination was evident in acid and detergent) (Dentsply Sirona, Tulsa the literature at that time (1960s)25. In 1971 there Dental Specialties, Tulsa, OK, USA) was either a casual mention of this issue14 or there • paraformaldehyde/formocresol gas were sporadic studies that addressed the issue22,26. • QMix (mixture of 3% NaOCl, 17% ethylene- However, a divergence of opinion existed at that diaminetetraacetic acid [EDTA], 2% chlorhexi- time as to the solution and time of exposure22 dine and polysorbate 80, a detergent) (Dent- (many authors advocated a minimum of 20 to sply Sirona, Tulsa Dental Specialties, Tulsa, OK, 30 minutes or longer without evidence for such USA) recommendations). Simplification of the process • glutaraldehyde 2% was supported by Ingle11 by merely wiping the • peracetic acid 2% cone with a sponge soaked in a germicide. • propolis Table 2 lists studies that have investigated the • miscellaneous commercial solutions disinfection of gutta-percha cones. In review- • antibiotics (wide range) ing the studies and data provided in this table, • electron beam. it should be noted that there was approximately a 10-year period from 1987 to 1998 when little An additional issue that emerged from a review of attention was paid to the evaluation of the decon- these studies was the concern as to whether or not tamination process for gutta-percha usage. Had there was an existence of a pattern between the the clinical community become complacent with time of exposure of the gutta-percha cones to the the data available or were there other aspects of environment and the potential for introducing a root canal procedures that were receiving greater microbial contaminant77. This would be a perplex- attention? Was it possible that during this time ing issue because of the wide range of research frame when dental clinicians began to wear gloves protocols and variables identified amongst the routinely, it was thought that this would prevent studies. However, in further research that simu- any contamination of the gutta-percha cones? lated this clinical situation, there was no clear Ironically, many of the studies reviewed for this time-related pattern of exposure and prediction paper identified that manual manipulation with of contamination77. In fact, environmental con- the fingers, gloved or not, contributed to enhanced tamination was found to occur only rarely, with the contamination of the cones, with Staphylococcus organisms identified to be nonpathogenic. organisms predominating. Upon further review of Furthermore, there were a number of stud- the studies, it is apparent that a large number of ies that carefully investigated the impact of the

ENDO EPT 2019;13(3):191–206 193 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation Requires special solution; time Requires needed; eliminates rapid decontamination. chairside disin- Rapid and effective fection with 5.25% NaOCl. in the lon; signiﬁcant differences of commer- bactericidal efﬁciency exist; cially available antimicrobials selection for a given situation must include differences. and applicable Clinically relevant with 5.25% NaOCl. procedure in 1 s recom- 2.5% dip effect mended. 10-min considerations not clinically for rapid decontamin- relevant ation. Rapid, chairside disinfection with 2.5% NaOCl. Rapid, chairside disinfection of GP cones can be achieved with 5.25% NaOCl. Time may be a factor when speed Time NaOCl not readily is required; available in a 4.5% concentration. effective against effective 2 O 2 tion. tion. contaminated. 5 min immersion with the NaOCl, 5 Zephiran and H 2. PVP-I for 4 min only 50% disinfec- PVP-I for 4 2. min, complete disinfec- PVP-I for 6 3. 1. Commercial cones not grossly cones not grossly Commercial 1. with all GP s immersion effect 60 cones using 5.25% NaOCl. Savlon (2% CHX) most effective. Rapid chairside with 2% Sav- Rapid decontamination with 5.25% NaOCl is feasible; all solutions spores. removed deliber- GP cones were Pre-sterilised ately contaminated with saliva and immersed in by handling; points were a 2.5% NaOCl for 1–10 s and then to the NaOCl A 1-s exposure cultured. in disinfecting the GP. was effective min, long-term at 10 While effective to solutions unknown exposure impact on the GP cones. regarding with 2.5% Short time exposure NaOCl. antibacterial and NaOCl has strong which depend on effects, sporocidal the liberation of active chlorine, a powerful oxidising agent that inacti- vates enzymes containing functional sulfhydryl groups. Gram-positive and endospore-forming Gram-positive and endospore-forming microorganisms. ; ethanol, eugenol, 2 O 2 Fungal spores killed by NaOCl and Fungal spores Zephiran but not H betadine, chloroform and iodine were not and iodine were betadine, chloroform surface sterilising agents. effective handling. elimin- bacterial kill at 45 s; spore Variable ation at 60 s. and spore microbes Savlon destroyed min. formers after 30 s to 1 min, and at 5 min, Sporcidin NaOCl at 1 contamination min reduced Cidex at 15 by 99.90%. disinfected Contaminated GP cones were within 1 s. CHX and NaOCl showed complete min; the two decontamination after 10 failed to sterilise ineffective alcohols were min; paraformaldehyde required at 10 overnight for disinfection. of contaminated GP cones 10-s exposure to the 2.5% NaOCl found be most in the surface disinfecting. effective the in destroying 5.25% NaOCl effective min of contact. Glutaral- after 1 spores dehyde, CHX and ethyl alcohol did not min decontaminate the GP cones after 10 contact. Results Conclusions Clinical implications . 2 O 2 CHX (Savlon); denatured alcohol CHX (Savlon); denatured 97%; alcohol 95%; immersion. 0.53% Zephiran; 3.00% H and Cidex) dehyde (Sporcidin 5.25% NaOCl – immersion. - blot on sterile cloth. paraformalde- alcohol; 50% isopropyl; hyde – immersion. aldehyde) and 10% (PVP-I) solutions for 10, 20 and 30 s. 2% CHX; 70% alcohol – immersion. technique 1971min. PVP-I 10% – immersion 10 s to 6 Contamination primarily due to clinician 1975 5.25% NaOCl – immersion. 1979 2% aqueous glutaraldehyde; 1.5% 1983min immersion – 4.5% NaOCl; 5 1983 solutions of glutaral- Commercial 1986 2.5% NaOCl - 1, 2, 3, 5 and 10 s dip 1987 2% CHX; 5.25% NaOCl; 70% ethyl 1987 (2% glutar- 2.5% NaOCl, Sporocidin 1998 5.25% NaOCl; 2% glutaraldehyde; 25 28 30 32 29 26 27 31 33 Suchde et al Linke and Chohayeb Ludlow and Hermsen Stabholz et al Misirligil and Erdogan Siqueira et al Senia et al Montgom- ery Study Year Decontamination substance/ Frank and Pelleu Table 2 Table cones Evaluative studies of merit on the decontamination/disinfection gutta-percha

194 ENDO EPT 2019;13(3):191–206 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation Following rapid chairside disinfection, the cones should be rinsed any crystallisation to remove of clinical relevance products; NaCl crystals that form after using the rapid-sterilisation technique the apical unknown regarding seal. Rapid, chairside disinfection with 1% NaOCl is achievable. canal sealer (AH-26) Use of a root added to the disinfection process. as an effective Not considered decontamination method for chairside application. Chairside decontamination is possible rapidly with all solutions – as low as 0.5% is effective. Neither would be able to used for rapid chairside disinfection based on parameters study. Although some cones from not unopened packages were contaminated, cold disinfection should be used. CHX has the shortest time effi- min up to 5 ciency; NaOCl required bacteria; however– spore-forming min study in 1999, 1 in the previous –with 1% NaOCl was effective these types of data support the high variability in the studies. -10 min; or by 2% glutaral- -10 2 O 2 NaCl crystals removed by 96% ethyl NaCl crystals removed alcohol, and alcohol, 70% isopropyl distilled water. GP cone may be disinfected by 2% min, or by 1% NaOCl, CHX for 1 min, or by 6% 10% PVP-I during 5 for H Immersion of cones for 1 min using Immersion of cones for 1 min with 0.5% 1% NaOCl or for 5 NaOCl is recommended. If no intentional contamination - disinfection unnecessary. by of microorganisms The reduction canal filling materials is clinically root The antibacterial not very effective. of the GP cones was different effect This for the tested microorganisms. as a microbial could be interpreted selection that may lead to a quantita- tive or qualitative shift in the composition of the specific microflora. to eliminate E. faecalis required Time depended on the concentration and type of irrigant used. NaOCl (2.5%) and 2.2% glutaralde- as to be effective hyde (Cidex) proved sterilising agents for GP cones, with shorter periods of NaOCl requiring use. For all GP cones chemical decontamination was achieved. GP cones may in contact with paraform- be stored h to achieve aldehyde vapours for 1 disinfection. dehyde for 15 min. dehyde for 15 All except 1% and 0.3% iodine alcohol bactericidal and 70% ethyl alcohol were after 1–5 mins; sporicidal 1–15 mins. After 1 min of treatment, the solutionsmin of treatment, After 1 tested showed bactericidal and sporicidal at concentrations of 0.25% and 1%,effects At a concentration of 0.25%, respectively. in effective the solutions tested were min of exposure. after 5 spores destroying the box from GP cones taken directly min immersion in 5.25% were - with 1 bacteria-free. No SSD was observed between the sterilised and unsterilised cones. Both the tested sterilised and unsterilised cones of pathogens, with no growth impaired influence of the time elapsed since sterilisation.* in killing E. effective All irrigants were times. Liquid CHX faecalis but at different all concentrations tested (0.2%, 1% and the most 2%) and NaOCl (5.25%) were by 0.2% irrigants; time required effective CHX liquid and 2% gel was only min, respectively. s and 1 30 after 5, 10 2.5% NaOCl was effective h contact 10 and 12 min, whereas and 15 with 2.2% glutaraldehyde was necessary to obtain sterilisation. on the GP cones No crystals present the box. All GP cones had from directly after the rapid-steri- NaCl crystals present lisation technique using 5.25% and 2.5% min. NaOCl – 1 over short Cold decontamination effective time periods. ; 10% 2 O 2 faecalis . PVP-I, for 1, 5, 10, and 15 min; 4 PVP-I, for 1, 5, 10, and 15 major bacterial species. alcohol; 1% and 0.3% iodine 2% glutaraldehyde; 6% H for a period of time; Cl; GP stored canal sealer added as a variable. root 5.25%) and two forms of CHX (gel concentrations and liquid) in three (0.2%, 1% and 2%) – immersion E. hyde (Cidex) as sterilising agents for min GP cones – immersion, 5, 10, 15 h for glutaralde- for NaOCl up to 12 hyde. – immersion evaluate the presence of solution crystallisation – 1-min immersion. aldehyde tablets. 1999 0.025% to 4.0% NaOCl – immersion. 2000 2% CHX; 1% NaOCl; 70% ethyl 2000 the box; 5.25% NaO- GP taken from 2001 sterilisation. Electron-beam 2001 NaOCl (0.5%, 1%, 2.5%, 4% and 2001 2.5% NaOCl and 2.2% glutaralde- 2003 2.5% and 5.25% solutions of NaOCl 2003 10% PVP-I; 5.25% NaOCl; paraform- 40 37 36 34 35 38 39 41 de Souza et al Cardoso et Cardoso al Attin et al Gomes et al da Motta et al Short et al Namazikhah et al Cardoso et Cardoso al

ENDO EPT 2019;13(3):191–206 195 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation Clinical relevance of the changes Clinical relevance requires in physical properties assessment. 0.5% NaOCl solution appears to be safe and rapid in the disinfection of GP cones. for 5.25% NaOCl is appropriate min. chairside disinfection at 1 for 2.5% NaOCl is appropriate chairside disinfection. but not rapid in CHX effective achieving complete decontamination. While disinfected, the GP cones anti- did not display residual activity in the time microbial tested; see* Three chemical disinfectants are effec- chemical disinfectants are Three tive agents for the rapid sterilisation of GP cones. 0.5% NaOCl solution did not cause any alteration on topography or elas- concen- greater whereas ticity of GP, trations impacted the GP. agent for 5.25% NaOCl is an effective a rapid disinfection of GP cones. NaOCl at 2.5% concentration is an agent for decontamination of effective GP cones at no additional cost. min for all at 5 2% CHX effective formers). (yeasts and spore microbes 5.25% NaOCl did not impart residual activity to GP cones. antimicrobial ; all disinfect- † † CHX was not effective in eliminating CHX was not effective h of contact on GP cones after 72 spores with the disinfecting substance. 5.25% GP after from NaOCl eliminated spores min of disinfection. The cones evaluated 1 their boxes did not show con- from tamination in 94.5% of the cases.* The found genus most frequently microbial after intentional contamination with gloves was Staphylococcus . ants were effective in the rapid disinfec- effective ants were min; tensile strength tion of GP cones at 1 between the NaOCl- and CHX-soaked but there was significantly different groups between the was no significant difference groups; NaOCl- and ChloraPrep-soaked thedisinfectants significantly increased elongation rate of the GP cones. Aggressive deteriorative effects on GP deteriorative effects Aggressive observed for 5.25% cone elasticity were to the min when compared NaOCl at 1 0.05). 2.5% and 5.25% < ( P control NaOCl solutions caused topographic to min when compared changes after 5 ( P < 0.05). the control sterilised with a 2.5% GP cones were the test. Glu- NaOCl solution throughout taraldehyde did not decontaminate the min of contact. GP cones even after 15 Some bacterial species eliminated in at least a 5-min min; some required 1 using both aqueous and deter- exposure gent solutions of CHX. the box were 19.4% of GP cones from contaminated, and all the species belonged to the genus Staphylococcus * Resilon cones exposed to CHX for 10, min demonstrated residual 20 and 30 antibacterial action and that substances did not cause alterations to the cones’ surface; unable to bind chemical agents were the GP cone components and to release themselves into the agar medium during all periods of time tested; no zones inhib- associated with the disinfectionition were with of 5.25% NaOCl in all tested periods. Results Conclusions Clinical implications P. gingivalis ; 1, E. faecalis and P. sion. 2.5 and 5.25% NaOCl on GP cones. 0.5%, 1%, 2.5%, 4% and 5.25%; - immediate, 45 s, and 1, 3, Times min in contact 5, 10, 15, 20, and 30 with the substances. For CHX, other min and 1, 2, 3, added: 45 times were h – immer- 5, 10, 12, 24, 48, and 72 – immersion. immersion. NaOCl; immersion; alterations in the and physical properties surface texture of GP cone after chemical sterilisation also compared. were and Resilon cones when exposed to 2% CHX gel and 5.25% NaOCl; to effects residual evaluate antimicrobial against min exposure. 5, 10, 20 and 30 technique 2005 Used AFM to study the impact of 0.5, 2005 CHX 0.2%, 1.0% and 2.0%; NaOCl 2006 2% glutaraldehyde and 2.5% NaOCl 2007min 2% CHX – 1, 5, 10 and 15 2007 2% CHX and 5.25% ChloraPrep, 2007 Alterations on the surface of GP 44 42 46 43 45 47 Gomes et al Gomes et al Redmerski et al Pang et al Valois et al Valois Study Year Decontamination substance/ Özalp et al Evaluative studies of merit on the decontamination/disinfection of gutta-percha cones 2 (cont.) Evaluative studies of merit on the decontamination/disinfection gutta-percha Table

196 ENDO EPT 2019;13(3):191–206 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation recom- 2 O 2 mended. Parameters not amenable to rapid chairside disinfection. While the numbers of these quite low at were microorganisms the time of opening package, clinical use of the packages the number of micro- increased contaminating the GP organisms cones. for effective 2% CHX was more chairside disinfection at the 1-min time period. Disinfection with commonly used substances may enhance the filling ultimate interaction of core materials with sealers. Supports the use of 2% peracetic acid for chairside disinfection. Clinical rinsing of cones that disinfected with NaOCl or were appears essential – may MTAD impair obturation seal with crystals attached. min for in 1 6% NaOCl effective chairside disinfection. aseptic in Although GP points are their package, once opened and used, GP cones may be con- to eliminate taminated. In order bacteria and not to cause surface changes on GP cones, disinfection solution must be selected carefully. was the most effective. Rapid chairside with H 2 O 2 H Spore forming microorganisms may be forming microorganisms Spore to kill. much harder sealed package harboured facturer’s Clinical use of the microorganisms. packages has been found to be associated with additional contamination of the GP cones; no SSD. to achieve 1% NaOCl was ineffective disinfection. desired Solutions used in decontamination pro- energy, the surface free increase moting high interaction between GP and Resilon sealers. 2% peracetic acid solution was effective against the biofilms of tested min on GP cones at 1 microorganisms of exposure. A final rinse is essential, especially used in are when NaOCl and MTAD the cones’ disinfection process. observed on No alterations were the GP cones, but it can change surface of Resilon cones. min than at 1 effective 2% CHX more 5.25% NaOCl; no alterations see on the surface of GP cones. chloride only 1 min. only 1 2 O 2 2% glutaraldehyde decontaminated cones min and 10 min; NaOCl required in 5 in the ineffective PVP-I and Savlon were time frames. contaminated at a low level.GP cones are manu- from GP cones taken directly Immersion of GP cones in 2% CHX for method for GP min was an effective 1 disinfection; 10% PVP-I and 1% NaOCl min of immersion to achieve needed 10 disinfection. the sur- Disinfectant solutions increased use of CHX presented energy; face free lower values of contact angle, followed by NaOCl when sealer used. was observed, after Significant reduction in the test solution; all min of exposure, 1 min. eliminated after 2.5 microbes Use of NaOCl without rinse - crystal formation on all samples; no of – presence change with CHX; MTAD a ppt. 6% NaOCl solution can be used in the disinfection of GP and Resilon cones. min Immersion of GP into 2% CHX for 1 method to was found the most effective eliminate the selected microorganisms. CHX and NaOCl required 10 mins for CHX and NaOCl required min and complete disinfection; alcohol 5 H ; 2% CHX; 1% NaOCl; 2 O 2 tion; 5% PVP-I solution; Savlon (1.5% for compared CHX) solutions were in sterilising GP cones effectiveness contaminated with Bacillus subtilis min. immersion 5, 10 and 15 spores packaging. manufacturer’s and 0.9% saline solution – immersion 1–10 min. of GP and Resilon cones after disinfection; investigate the wettability of root canal sealers in contact with these surfaces; CHX and 5.25% NaOCl. of GP cones contaminated in vitro with multiple bacterial species; immer- min. sion 1–2.5 after immersion with and without rins- min; SEM/EDX analysis. ing – 1 min – immersion; 1, 5, 10, 20 and 30 AFM/SEM/EDX. possible surface changes caused by 5.25% NaOCl, 2.5% 2% CHX; 0.05% Octenisept on GP cones min. – immersion; 1, 5 and 10 70% ethyl alcohol - immersion for 1, min. 5, 10 and 15 2008 4% NaOCl; 2% glutaraldehyde solu- 2009 the from Evaluation of GP directly 2010 6% H 2011 1% NaOCl; 2% CHX; 10% PVP-I 2011 energy Evaluation of the surface free 2011 2% peracetic acid for the disinfection 2011 5.25% NaOCl, 2% CHX and MTAD; 2011 6% NaOCl on GP and Resilon cones; 2011 antibacterial effects; Possible residual 55 52 54 53 48 50 51 56 49 Nabeshima et al Kayaoglu et al et al Taha Prado et al Salvia et al Prado et al et al Topuz Sahinkesen et al Rana et al

ENDO EPT 2019;13(3):191–206 197 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation . 60 Effective result but not as rapid result Effective NaOCl. Wide variety of disinfecting agents Wide for rapid chairside activity within 30 s. Concentrations of NaOCl at or for below 0.5% may be effective decontamination when used in combination with ethyl alcohol rinse. Possibly the use of CHX might be prior to obturation – note favoured sealer used with GP; may resin not be the same with a bioceramic sealer. Alternative to NaOCl? min disinfection in NaOCl 1 acceptable but do not exceed that alteration in time frame to prevent apical fit. the cones regarding Alternatives to NaOCl effective; % of NaOCl not as effective lower for rapid disinfection. min a rapid method; impact on 5 min may be a concern cones at 5 to other studies, i.e. Spoleti relative et al Rapid chairside disinfection can min with the be achieved within 1 solutions tested (as low as 3.7% NaOCl). Rapid chairside management with 5% NaOCl. , 2% 2 GP cones do get contaminated during due canal procedures storage and root to glove handling. CHX, and QMix might be used as agents for rapidly disinfecting effective contaminated GP points after 30 s. No contamination present in new No contamination present sealed boxes of GP cones; 30 s immersion in 0.5% NaOCl was sufficient for decontamination of GP cones contaminated with E. faecalis and saliva. Decontamination of GP and Resilon in higher cones with 2% CHX resulted Fad values. decontaminated the min exposure 1 GP cones. con- the box were No GP cones from taminated; impact of disinfected cones by in their apical fit may be affected longer disinfection times in NaOCl. 1% peracetic acid and 2% CHX were the best and better than 3% NaOCl. complete disinfection and a final rinse of GP cones with distilled water is essential to eliminate the surface deposits. of NaOCl evaluated. percentages All disinfectant agents were effective effective All disinfectant agents were in sterilising the GP cones. 5% NaOCl and combination of CHX disinfected cones with the immersion time of 1 min. All four tested were effective within 30 s. effective All four tested were 2.5% NaOCl, CaOCl ethyl alcohol was just as effective for ethyl alcohol was just as effective decontamination of GP cones as 5.25% NaOCl followed by a rinse in alcohol. Higher Fad between solid filling materials canal sealers was found when and root with CHX solution was used. Treatment NaOCl solution did not influence Fad values (AH Plus and Real Seal SE). as decontam- Aloe vera was effective inant. min; do not disinfection at 1 Effective exceed. 1% peracetic acid showed the best results min; 2% CHX showed the for 1 and 5 although it was stat- second best results istically at par with peracetic acid; 3% in disinfection; statis- NaOCl ranked third tically significant. against inoculated Herbal gels effective min. 3 bacteria; required > NaOCl 2% CHX.Disinfection > MTAD 5-min immersion is required for the effective. examined were All protocols at the min of immersion sufficient 1 Results Conclusions Clinical implications Most effective – 5% NaOCl and CHX Most effective Cetrimide combination. ; 2% 2 ; combination of 2 O 2 CHX; QMix; 6.5% grape seed extract; four evaluation periods (30, 60, 90, and 120 s) immersion. canal sealers, GP and Resilon cones following disinfection - immersion; AFM; 5.25% NaOCl/2% CHX. the Aloe vera extract/gel – to prevent of crystals formed by NaOCl. presence rinsed with alcohol. acid, and 10% PVP-I in the rapid disinfection of Resilon and GP; 1 5 min immersion. alcohol; 3% H used as gels; 5.25% turmeric were min immersion. 3 NaOCl – control; min. min and 5 1 immersion. technique 1.5% CHX and 15% Cetrimide in clinical conditions – equal proportions; min immersion. 1, 3, 5, 7, and 10 2011 0.5% and 5.25% NaOCl – immersion. 0.5% NaOCl followed by a rinse in 100% 2012 (Fad) between root Adhesion force 2012 2013min - immersion; 5.25% NaOCl for 1 2013 3% NaOCl, 2% CHX, 1% peracetic 2013 5% PVP-I, NaOCl; 95% ethyl 2014 Extracts of Aloe vera , neem bark and 2014 30 s, 5.25% NaOCl; 2% CHX; MTAD; 2014min – 3.7% and 5.8% NaOCl for 1–3 2015 2.5% NaOCl; CaOCl 65 61 57 64 58 59 60 62 63 66 Chandrappa et al de Assis et al Athiban et al Spoleti et al Subba et al Pradeep et al Schmidt et al Shnay- dman Study Year Decontamination substance/ Jiménez- Badilla et al Shenoi et al Evaluative studies of merit on the decontamination/disinfection of gutta-percha cones 2 (cont.) Evaluative studies of merit on the decontamination/disinfection gutta-percha Table

198 ENDO EPT 2019;13(3):191–206 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation Two solutions that can provide solutions that can provide Two rapid chairside disinfection. min so as Minimise contact to 1 not to alter the surface of cone. Lower concentration of NaOCl for chairside disinfection. effective changes caused by Topographic peracetic acid should be evaluated on further to determine its effect and obturation seal. GP properties cones Practicality of treating with CHX questionable when by themselves in NaOCl seem to be effective. While herbal solutions effective, for rapid chair- data not relevant side disinfection. Changes in surface characteristics minimal when the of GP cones are min; immersed for 5 cones were this may lead to better adaptability of the cone to sealer and canal wall. than NaOCl in GP effective more cone disinfection. management of GP cones Careful containers essential taken from using sterile instruments. inef- Demineralising solutions were fective in disinfection. 5.25% NaOCl and MTAD effective effective 5.25% NaOCl and MTAD min. within 1 min but with at 5 and 10 All effective alterations of the cone surface at those time periods. PVP-I had not effective; Propolis minimal disinfection impact even at 10 min. All agents impacted on the surface of the GP cones; 20% cones min with 3% at 1 showed growth NaOCl. CHX coated cones better than grape seed extract and NaOCl. in All the herbal solutions effective disinfection of GP cones; Pancha Tulsi possessed superior antibacterial activ- with Aloe vera ity when compared juice and Amla juice. NaOCl immersion significantly the RMS values of GP decreased as the concentration of NaOCl was 0.5% to 5.25%; from increased min 5.25% NaOCl immersion for 5 but surface roughness decreased significantly at increased roughness min with 5.25% NaOCl. 10 min. at 5 and 10 NaOCl least effective Alternative solutions appeared No need for decontamination of GP cones as long the chain of asepsis is respected. time, of the exposure Regardless the most 1% and 2.5% NaOCl were effective. 5.25% NaOCl required 1 min exposure min exposure 1 5.25% NaOCl required disinfection of all the sam- for effective min; – 30 s; Resilon cones 1 ples; MTAD min. 2% CHX and CFC – 5 No SSD in the disinfection quality; SEM/ EDS analyses showed no alteration in the of cones after immer- superficial features sion. Immersion of GP cones in a solution min is 2% CHX and 3% NaOCl for 1 their method to promote an efficient disinfection. 1% peracetic acid was most effective agent; 0.5% Octenisept was the least min. no SSD at 1 or 5 effective; Concentrations of NaOCl 2.5% and 5% activity against spore showed reduced forming bacteria. ( P < 0.01); among the groups SSD present was found to be most effec- Pancha Tulsi tive disinfectant followed by Amla juice. SSD in the values between 0.5%, 2.5% and 5.25% NaOCl ( P < 0.05); was no SSD between 0.5% NaOCl and control 0.05); RMS used with AFM to > ( P group evaluate the surface topography. min at 5/10 – no difference Propolis zone of bacterial inhibition; – largest min; Prop- Other solutions SSD at 5/10 olis > Aloe vera CHX NaOCl. or experimen- None of the cones, control contaminated upon evaluation. tal were Morphological changes in the cones after to NaOC. Other solutions min exposure 5 changes at all time frames. created . 73,74 (a combination of calcium hydroxide, (a combination of calcium hydroxide, – immersion. Flagyl and ciprofloxacin) acetic acid; QMix – immersion 5 and 10 min. CHX; 10% PVP-I and 0.9% NaCl to disinfect GP cones contaminated by E. min. faecalis – immersion 1 and 10 Octenisept in disinfecting GP cones – min; analysis of surface alterations 1–5 of GP cones after chemical disinfection. grape seed extract; cones treated min exposures with 2% CHX; 1 and 5 bacteria. Aloe vera juice; Amla Pancha 7-day assessment. Tulsi; min and min, 5 de-ionised water for 2 min immersion time; Topographical 10 analysis in AFM. – immersion 5 and vera ; 10% propolis 10 min. and 0.12% CHX - immersion for 1 min. 10% citric 5% malic acid; 17% EDTA; acid; 1% and 2.5% NaOCl for 1, 5 min immersion. and 10 2015 2% CHX; CFC 5.25% NaOCl; MTAD; 2015 5.25% NaOCl; 2% CHX; 1% per- 2015 extract, 3% NaOCl; 2% 30% propolis 2016 3% NaOCl, 1% peracetic acid, 0.5% 2016 2% CHX; 5% and 2.5% NaOCl vs. 2017 2017 0.5%, 2.5%, 5.25% NaOCl and 2017 5.25% NaOCl; 2% CHX; 20% Aloe 2017 2.5% NaOCl; 70% alcohol; 2% CHX 2018 Sterilized GP cones; contaminated; 75 70 68 73 74 69 67 71 72 76 Tüker et al Tüker Raveendran et al et al Yadav Ummer et al Mukka et al John et al Nair and Bandhe Matos et al de Miranda et Candeiro al Hamza et al Contamination from hand or glove. Contamination from AFM, atomic force microscope; EDTA, ethylenediaminetetraacetic acid; EDX, energy dispersive x-rays; GP, gutta-percha; RMS, root mean square; SSD, statistically significant difference. SSD, statistically significant difference. mean square; RMS, root gutta-percha; dispersive x-rays; GP, ethylenediaminetetraacetic acid; EDX, energy EDTA, microscope; AFM, atomic force and Genet *Also verified by Moorer †

ENDO EPT 2019;13(3):191–206 199 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation

disinfection solutions on the surface topography of Relative to the proprietary nature of the gutta- the gutta-percha cones using either atomic force percha and its zinc oxide component, Friedman microscopy (AFM) or scanning electron micros- et al7 reported in 1975, after assessing five differ- copy (SEM) and energy dispersive x-rays (EDS/ ent brands of gutta-percha cones, that the mean EDX) to determine if there had been any signifi- percentage of zinc oxide was 66% with a range cant alterations42,54,55,58,73. This was significant of 59.1% to 75.3%. However, this information as changes were noted in the gutta-percha cones does not necessarily reflect on present-day com- with the increased NaOCl percentages and time position. Furthermore, the nature of this variability exposure42, although not all studies were in agree- may impact on the activity of different cones based ment with this type of outcome55,58,73. on the identified ability of the zinc oxide compo- When 2% peracetic acid was used, Yadav et al70 nent to be somewhat antimicrobial73,74. In their identified changes in the gutta-percha cones that study, Moorer and Genet74 used “microbiologic were considered as potentially impacting on canal analysis, measurement of osmolarity, microscopy, obturation and seal, an issue worthy of further x-ray diffraction analysis, and scanning electron investigation. The concern about leaving cones in micrography … to identify the biologically active solution for long periods of time was already ech- component that slowly leaches from gutta-percha oed by Nygaard-Ostby in 1971 … “Points should cones. This component is zinc oxide in the form never be kept permanently in a fluid disinfectant of small solid particles, from which active, soluble as this is liable to make them soft”14. Zn2+ ion is mobilized by hydrolysis. A hypothesis Many variables exist amongst the studies cited on the ‘depot’ effect of the ZnO particles is for- in Table 2, including the choice of organisms/ mulated”74. In their microbiological analysis, they spore forming entities used to contaminate the noted that the growth of Staphylococcus aureus in gutta-percha and the culturing process; whether serum could be abolished by the “mere presence the cones were air dried or not prior to plating in of gutta-percha”73. Therefore, it is possible that in bacterial cultures or added to culture media and many of the studies listed in Table 2, the impact time involved; sample sizes relative to the number of the zinc oxide component in the disinfection of cones used; the presence of contamination on (not sterilisation) was not considered, which was the cones when removed from the packages; the dependent on the percentage of zinc oxide and its degree of bacterial contamination; evaluation of rate of release from the cones. turbidity when a positive culture was present; time From a clinical standpoint, historically it might variability throughout the entire evaluation pro- take two to three or more cones to find the right fit cess; the proprietary nature of the gutta-percha in the canal, especially when using cones with a .02 and its zinc oxide component; and the nature of taper or cones of greater taper. Furthermore, many the NaOCl concentrations, whether used directly clinical scenarios required the cutting off of small from the clinical source or diluted to a specific amounts of the cone apically to establish a better fit percentage, and its accuracy in the process of as opposed to going to a larger size75-77; in some situ- dilution. ations the use of a solvent, such as chloroform, to It would be very difficult to make meaningful create a custom fit cone was advocated76,77; even a comparisons from a microbiological standpoint, reshaping of the canal was recommended in specific because of the variability of the nature of the organ- situations75. Moreover, under these circumstances, isms used in these studies and especially if spore it was highly possible that the cones became con- forming bacteria were used. In clinical practice, the taminated beyond what may have been present in microbicidal action probably would be greater than their packaging22. Hence, additional decontamin- that demonstrated in some studies, because the ation would have been necessary and for clinical natural contamination of cones in most of the cases efficiency, a rapid chairside way of accomplishing would be considerably less and consist mainly of this was necessary. However, contemporarily, gutta- vegetative bacteria rather than resistant spores48. percha cones are being manufactured to more

200 ENDO EPT 2019;13(3):191–206 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation

accurately fit into the shaped canal space, such as less extreme with a lower percentage of the NaOCl; the Conform Fit Cones (Dentsply Sirona, Ballaigues, therefore, in teeth with open apices requiring root Switzerland), which should minimise or negate the canal procedures a lower percentage would be rec- excessive handling of the cones. However, a rapid ommended by many clinicians/authors. chairside decontamination process would still be In the United States, a major manufacturer considered as part of the chain of asepsis during of bleach (Clorox; The Clorox Company, Irving, root canal procedures. Texas, USA), changed the percentage of NaOCl from 5.25% to 6.00% (labelled as Cloromax) in 2000, without a major announcement to the daily Percentages of NaOCl used in the users of this substance, and certainly not to the assessment studies dental profession. This was done to stabilise the product for long-term use. Whether or not this The use of NaOCl (0.5%) in the management of percentage is available worldwide is unknown, antisepsis occurred a little over 100 years ago dur- as it can be seen that the vast majority of global ing World War I in the form of what is known studies cited in Table 2 have used 5.25% NaOCl. today as Dakin’s solution78. Its use as a tissue solv- As of 1 November 2013, Clorox changed the per- ent in root canal surgery was identified by Johnson centage further to 8.25%. Most clinicians iden- and Waerhaug79 to be introduced by Mayrhofer tified this change by the colour of the solution in 1912 as Antiformin, consisting of 5.6% NaOCl and the much stronger odour than was usually and 7.5% Na(OH)2. Contemporarily, the percent- present during normal clinical procedures. Formu- age of the NaOCl used varies in both its source and lary changes in bleaching solutions globally may worldwide location. Its use may range from 0.5% also have undergone variable modifications, so it to 8.25% depending on the purpose of its applica- is imperative that the clinician knows the specific tion; for example, when used in a cavity prepar- formulation being used in the dental surgery. ation to assist in caries removal or to clean the cav- The comprehensive assessment of the studies, ity it may be 0.5%; or as a root canal irrigant, a low presented in Table 2, shows that 24 studies evaluated percentage (0.5%) has also been recommended, the use of 5.25% NaOCl, with many evaluating a although for years the standard ranged from 1% wide range of percentages. The highest percentage to 5.25%. The latter percentage was popular for a evaluated was 6.0% (one study)55 with 13 studies number of reasons: evaluating 2.5%, which was a commonly used dilu- • it was easily obtained in the form of household tion. In actuality, 1:1 dilution of a 5.25% solution bleach at that percentage would have yielded a 2.62% solution and not a • it could easily be diluted 1:1 with distilled water 2.5% solution81. Few studies may have addressed for a less aggressive solution (2.5%) or 1:4 for the nature of their solutions with precision in this a 1% solution regard. With time being a factor along with clinical • it was available worldwide at the 5.25% con- efficiency, those studies that found 5.25% NaOCl centration. effective within a 1-minute period most likely reflect what is done clinically, when it is carried out to dis- These altered dilutions were recommended by many infect gutta-percha cones. There were seven studies authors to reduce the possibility of tissue damage at that found that 5.25% (one at 5%) was effective at the root apex and by those who chose not to isolate 1 minute; two studies indicated that 2.5% NaOCl the tooth to be treated with a dental dam, thereby was effective in that time frame; two studies ident- protecting the patient from having the solution ified a 1% solution as being effective – with one enter the oral cavity and cause the patient distress. indicating that it was ineffective; and two studies Additionally, if the solution was expressed beyond found that 0.5% was effective within the 1-min- the root end under pressure into the tissues, the ute time frame. Other observations included one ‘hypochlorite accident’80 as it is known, might be study that found that 10 minutes was necessary for

ENDO EPT 2019;13(3):191–206 201 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation

complete disinfection; while three studies indicated may also benefit the disinfection of the core-carrier that 5 minutes was necessary and one study stated gutta-percha, with the additional heating of obtur- that even at 5 and 10 minutes NaOCl was the least ator enhancing the antimicrobial activity. Investiga- effective disinfectant. These findings all emphasise tions in this direction would be warranted. Like- the variable nature of the studies and the major wise, because of the potential for NaOCl crystals differences in the evaluative mechanisms. to form on the gutta-percha cones, wiping them Two alternative solutions for decontamination or rinsing with 70% to 95% alcohol upon removal deserve some consideration based on research from the NaOCl solution may be appropriate40,54. findings: 2% chlorhexidine gluconate (CHX)51,58 Moreover, it is possible that gutta-percha cones dis- and 2% peracetic acid53,61; even MTAD and QMix infected thoroughly with NaOCl may actually retard were shown to be favourable64,66,67. Significant dif- the growth of biofilms from bacteria that may be ferences in the bactericidal efficiency of commer- retained in the root canal at time of obturation. Here cially available antimicrobial chemicals exist, and again, further investigations into this interesting and selection of a chemosteriliser for a given situation meaningful possibility are warranted. must include consideration of these differences; for Based on the data available in the last 20 years example, Suchde et al27 in 1979 found that 2% of evaluation, can contemporary recommenda- CHX (Savlon, Chemical Corporation of India, Bom- tions be made? Recommendations can be made bay, Madras, Calcutta, India) was highly effective but their foundations may be weak and somewhat within 30 seconds to 1 minute even on spore form- empirically based. A focus could be on proced- ing microorganisms27, whereas Rana et al48 in 2008 ural outcomes, but too many variables, such as found that Savlon was ineffective. Questions arise the sealer and its distribution, may influence the as to whether or not formulations/percentages had findings, and dilute the true impact of a disinfected changed over a 20-year period. Furthermore, with gutta-percha filling material. Hence, based on the the use of 1% or 2% peracetic acid, will there be data available in the studies examined, literature residual effects retained by the gutta-percha cones reviewed and textbooks consulted82-86, the follow- that may impact on the obturation seal?70 ing considerations would seem to be appropriate There is an additional issue or technique that for rapid chairside decontamination/disinfection. has not received much attention in the literature • Minimise handling of the gutta-percha cones regarding the decontamination of gutta-percha with fingers, gloved or not, as the main con- cones, that being the clinical technique which is taminant has been identified as Staphylococcus. practiced by many globally: the wiping of the mas- • Use sterilised forceps in the handling of the ter cone with any of the above evaluated solutions, master and accessory cones. solely or in conjunction with immersion. Ingle11 • Immerse the cones in a 2.5% to 5.25% (or described this technique briefly in 1965. This may stronger) NaOCl solution for 1 minute; if greater be an efficient and rapid chairside technique, es- than 5.25%, reduction in time to 30 seconds pecially in light of the popular practice of single may be sufficient; it is possible that in cases of cone obturation. Wiping may consist of merely a controlled manufacturing, where contamination vertical/horizontal movement with a 2 × 2 cm cot- can be minimised, a 0.5% or 1% solution may ton sponge soaked in the chosen solution or it may be sufficient for cones immediately removed consist of a circular, circumferential wiping, moving from the sealed packaging; however, with 1% in a vertical or horizontal direction. It is possible that NaOCl a minimum time of 1 minute is still rec- this technique is performed often on cones immedi- ommended and with 0.5%, 5 minutes is recom- ately removed from their packaging prior to place- mended, depending on the concentration of the ment in the shaped and disinfected root canal, and solution that is used for the dilution. considered to be acceptable, although the degree of • Rinse the cones with alcohol 50% to 95% for 5 contamination was found to be low in cones taken to 10 seconds to remove any crystals of NaOCl from their packaging26,46,49,56,63,73. This procedure that may have formed.

202 ENDO EPT 2019;13(3):191–206 Gutmann and Manjarrés Disinfection of gutta-percha cones prior to obturation

• Wipe the gutta-percha cones with sterile gauze canal. The concept may warrant further investiga- soaked in a disinfectant as an additional level of tion using newer methods of assessment as to their decontamination; for example, alcohol, NaOCl, viability and clinical application. CHX. Various percentages of hypochlorite solutions • Heat the cone, via an oven for core-carrier continue to have many uses within the dental/ products or vertical compaction with a heated healthcare setting. Facilities, such as private ofﬁces/ compactor for potential enhancement of the clinics, dental colleges, etc. that use hypochlorite decontamination process; merely placing the should develop policies that comply with recom- master cone in the canal and cutting it off mended use concentrations, dilutions, storage, without any heat-aided compaction will not safety, and contact times. Despite the introduc- enhance microbial control. tion of new disinfectants, the many advantages of • Avoid long-term exposure of gutta-percha chlorine are likely to lead to its continued use in the cones to disinfecting solutions that may impact dental setting for the foreseeable future. on the surface of the gutta-percha and interfere with the ultimate obturation seal.

A ﬁnal area of investigation that may be tangential References

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95. Alagarsamy V, Rajesh Ebenezar AV, Srinivasan MR, 102. Oztan MD, Kiyan M, Gerceker D. Antimicrobial effect, George Mohan AG, Kumar S. Effectiveness of calcium in vitro, of gutta-percha points containing root canal hydroxide plus points and chlorhexidine active points medications against yeast and Enterococcus faecalis. against Enterococcus faecalis by agar diffusion test: an Oral Surg Oral Med Oral Pathol Oral Radiol Endod in-vitro study. J Restor Dent 2013;1:18–21. 2006;102:410–416. 96. Bozza RL, Molgatini SL, Pérez SB, Tejerina DP, Pérez 103. Wang D, Wang Z, Gao J. The development and in vitro Tito RI, Kaplan AE. Antimicrobial effect in vitro of chlor- release rate determination of controlled-release delivery hexidine and calcium hydroxide impregnated gutta- gutta-percha point containing metronidazole compound. percha points. Acta Otontol Latintoam 2005;18:51–56. Hua Xi Kou Qiang Yi Xue Za Zhi 2003;21:361–363. 97. Naik B, Shetty S, Yeli M. Antimicrobial activity of gutta- 104. Gao J, Wang ZP, Li XG, Wang D, Zhang L. The prepar- percha points containing root canal medications against ation and in vitro release test of sustained release delivery E. faecalis and Candida albicans in simulated root canals: gutta-percha point containing metronidazole. Shanghai an in vitro study. Endodontology 2013;25:8–18. Kou Qiang Yi Xue 2004;13:557–560. 98. Lui JN, Sae-Lim V, Song KP, Chen NN. In vitro antimicrobial 105. Vijay R, Suman M, Shashikala K. Evaluation of anti- effect of chlorhexidine-impregnated gutta percha points microbial efficacy of tetracycline gutta percha and calci- on Enterococcus faecalis. Int Endod J 2004;37:105–113. um hydroxide impregnated gutta percha against Entero- 99. Taqa AA, Suliman RT, Shehab EY. Evaluation of anti- coccus faecalis: an in vitro study. Indian J Dent Advance microbial effect for chlorhexidine incorporated gutta 2010;2:248–552. percha using FTIR spectroscopy. Int J Enhanced Res Sci 106. Jain VM, Karibasappa GN, Dodamani AS, Vishwakarma Tech Eng 2014;3:313–318. PK, Gaurao Vasant Mali GV. Comparative assessment of 100. Jhamb A, Chaurasia VR, Masamatti VKS, Agarwas JH, antimicrobial efficacy of different antibiotic coated gutta- Tiwari S, Nair D. In vitro evaluation of antimicrobial activ- percha cones on Enterococcus faecalis: an in vitro study. ity of different gutta-percha points and calcium hydroxide J Clin Diag Res 2016;10:ZC65–ZC68. pastes. J Int Soc Prev Community Dent 2014;4:92–95. 107. Tomino M, Nagano K, Hayashi T, Kuroki K, Kawai T. Anti- 101. Lohbauer U, Gambarini G, Ebert J, Dasch W, Petschelt A. microbial efficacy of gutta-percha supplemented with Calcium release and pH-characteristics of calcium hydro- cetylpyridinium chloride. J Oral Sci 2016;58:277–282. xide plus points. Int Endod J 2005:38:683–689.

James L. Gutmann, DDS, Cert Endo, Vivian Manjarrés, DDS, Cert Endo, PhD, FICD, FACD, FADI, FAAHD, FAAHD FDSRCSEd Assistant Professor, Endodontics, Health Professor Emeritus, Restorative Sciences/ Professions Division, College of Dental Endodontics, Texas A&M University, Col- Medicine, Nova Southeastern University, lege of Dentistry, Dallas, Texas, USA Davie, Florida, USA

James L. Gutmann

Correspondence to: Professor James L. Gutmann, 3212 Basil Court, Dallas, Texas 75204-5543, USA. E-mail: [email protected]

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