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

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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 qual- ity 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
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