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Dental Tribune United Kingdom Edition

November 201318 Endo Tribune United Kingdom Edition treatments and due to this ex- perience he asked me to repre- sent the N2 method in German speaking countries. After I had studied the endodontic scientif- ic literature, prepared a lecture in English and presented ump- teen treatment cases to the AES (American Endodontic Society= professional association of N2 users in the US), Sargenti paid for my trip to an AES session in the United States, where I re- ceived the “fellowship”. After presentation of yet another lec- ture and 150 completed cases I was bestowed the title of “mas- tership”. My mentioning of more than 16,000 treatments does not nec- essarily mean that they all met high quality standards. Root canal treatment of molars was quite in disorder. Until mid of 1985, however, X-ray control di- rectly after root canal treatment was only done in exceptional cases, so we did not know what we were doing. Consequently, frequent failures due to poor root filling quality could be ob- served after years. At least this proved that the Sargenti meth- od does not necessarily protect against failures due to poor root filling quality. In case of heavy overfilling, I prophylactically made a “Schröder Airation” (= artificial fistulation). In most of the cases, gangrenous teeth could also be treated in one ap- pointment. In case of short root filling, I finished treatment by apectomy; the other teeth were treated by trephination. Whether apectomy or treph- ination 2 – treatment has to be done efficiently without much fumbling to avoid subsequent problems. Acute exacerbations do very rarely occur after apec- tomy/trephination. I occasion- ally treated a “via falsa” with perforation and N2 leakage into the bone successfully by fistulation as well. I use the ex- pression “occasionally” as this happened only very rarely, thus there had been little chance to do the therapy. Basically I re- gard the perforation area as ar- tificial foramen, a foramen not belonging here. In few cases, I tried Diaket out as root filling material with following fistulation. Treatment is also successful with Diaket, however, I mind that it doesn’t pour off the lentulo the perfect way N2 does. It hardens as fast as N2, though. Root filling was followed by a possible apecto- my/fistulation after 20 minutes. I also know surgeons who use either N2 or Diaket. What does the N2 method comprise? • No canal rinsing • Use of the reamer as sole root canal instrument • Rubberdam for safety’s sake for manual manipulations only • Use of the strongly antimi- crobial N2 as root canal filling material (the powder contains five per cent formaldehyde, EU approval as medical device 6/1998) • Root canal treatment in one appointment is the goal (no problem in vital teeth, in non- vital teeth with reservation – in the latter case definitely com- plete reaming during the same appointment). Alternatively in one appointment finished by “Schröder Airation”. According to Sargenti, the “Schröder Ai- ration” comprises a wide treat- ment spectrum: pain prophylax- is during root canal treatment of non-vital teeth in one ap- pointment plus after overfilling of vital teeth roots, apart from that for pain therapy • According to Sargenti, point condensation of the root filling is not necessary, however, it looks better on X-ray What do you think about the frequently discussed ingredi- ent formaldehyde: Systemic distribution in the body ac- cording to literature? There is only an ambivalent an- swer to this question. The Block study with dogs as test animals circulates in literature. First of all, it has to be made clear that results from animal experi- ments cannot simply be adopt- ed for humans due to different metabolisms. So formaldehyde features different half-lives in different animal species. In hu- mans, half-life of formaldehyde amounts to 1 – 1.5 minutes. In an N2 court hearing in the US, the former leading US toxicolo- gist Brent stated that the results of the Block study had been misinterpreted. Due to the short half-life, formaldehyde had no longer bonded to marker C14. Correctly, the systemic distri- bution of C14 in the organs had been detected, however no for- maldehyde. At this point, I also wish to criticise laboratory tests (in vitro). An adoption of such results has to be judged skepti- cally as the enzymes of the liv- ing organism are missing. Have you ever experienced intolerances or allergic reac- tions to N2 in your practice? I have never seen an immediate or time-delayed allergic reac- tion although, to my knowledge, five of my patients, who have been provided with N2 root fill- ings, actually do suffer from for- maldehyde allergy. Surely the (not verified) estimated num- ber of unreported cases might have been much higher. As can be learned from literature, al- lergies against dental material do occur extremely rarely. In addition, self-reported cases do not necessarily stand up to sci- entific examinations. There is a lot of criticism against N2. What do you think about this and what would you answer the critics? Counter question should be whether the respective critic re- fers to literature or whether the argumentation is based on own practical experience. A hand- ful of cases are not sufficient, though. Regarding literature, it has to be clarified whether a so- called “publication bias” does exist, meaning that disagree- able results are not even being published. What do you think is the rea- son for the fact that the N2 method is accepted in other countries? Despite of professorship con- cerns, N2 has been approved in the EU. Even Sweden has reaccepted the method in 2011 as in some publications, the es- tablished endo could not have been presented convincingly – and especially it could not have been proven that newer methods deliver better results. In Oral Surg Oral Med Oral Pa- thology 2002, 94 (6): 651 – 652, Figdor G. had recorded that en- dodontics have only achieved a modest progress over the last 100 years. This complies with the statement of NgY et al. in Int. Endot J 2008, 41:6-31 “Outcome of root canal treatment: system- atic reviews of literature – Part 2 Influence of clinical factors”. As dental technology had pro- gressed strongly within the last 40 – 50 years, a higher probabil- ity of success could have been expected. Endodontists, howev- er, deny this non-increase stat- ing that they are treating more risky endodontic cases now. I’d like to add that the AES has in vain struggled to obtain N2 approval by the FDA (Food and Drug Association, respon- sible for approval of medical devices) for many years now. It is not a comfort for the local N2 users that so far also no other root canal filling material ob- tained an approval. It is shame- ful that hundreds of X-ray pho- tos required by the FDA could not be relocated by the FDA. Is there any evidence of can- cerogenity or mutagenicity from your point of view? Cancerogenity or mutagenicity could not have been proven by now. However, formaldehyde has been classified as human cancerogene some years ago, i.e. for pharyngeal tumor after consumption of a high dosage. Like in many cases, the same rule must be obeyed: Toxicity depends on the dosage. Still the statement on formaldehyde of the German Federal Medical Association (Dt. Ärzteblatt 1987; 84, issue 45: B 2107 – 82112) comprising that exceeding of a threshold value is the precon- dition for cancerogenity keeps validity. What are your experiences with histological examina- tions and their healing? Blind studies should be done, which, to my knowledge, do not yet exist. Test arrangements, the kind of cuts, definition of normality and aberrations are important factors in histology – according to Brynolf only seven per cent of the histologically examined endo teeth are free from inflammation. And every colleague has surely made the experience of false negative resp. false positive X-ray find- ings. Apart from that, evalua- tion of one and the same X-ray picture, done at intervals of some months, often results in a different diagnosis. Have their ever been com- plaints or discontent with N2 treatment from the patients’ side? No. What do you think about mul- tiply described paresthesia or dysesthesia after N2 treat- ment? I wrote on these topics in “Endo- dontie 4/1999: 323 – 336: Dam- age to the N. alveolaris inferior by overfilling with root canal material”. I could refer to a sim- ilar article by Kockapan with his statement that the frequently reported nerve damages caused by N2 cannot be ascribed to the physical characteristics of the material but to its worldwide use. Naturally, such incidents are only published with some years’ delay. Unfortunately, the use of N2 has strongly been de- creasing for years, which can- not only be attributed to the statements of the professor- ships but is also caused by the variety of new products. Each and every new technique and promoted root canal filling ma- terial on the healthcare market claims to offer a sophisticated procedure respectively material in the patients’ and practioners’ interest. Could you ever blame your colleagues for taking hold of the new products? Have you ever observed bone or gingival necrosis after the use of N2? I had to diagnose a gingival ne- crosis only once after following Sargenti’s proposal to put an N2-soaked stripe of tamponade into the gingival pocket. DT Publications: Schädigung des Nervus alveo- laris inferior durch überfül- ltes Wurzelkanalfüllmaterial.. Endodontie #4; 1999: 323-336; Endodontic treatment of pri- mary teeth in the general dental Practice. Roots Vol 6: 2010(3): 26-30 Vital amputation of per- manent teeth. Roots . 2011; 4: 10-16 About the author Dr. Robert Teeu- wen • Born 1937 • Studied Univer- sity of Bonn, Germany • Approbation 1965 • Opening of dental practice 1969 • Joint practice with son 1994 – 9/2005 • Retired from active dentistry 9/2006 page 17DTß Fig 9 Product Shot Fig 7 Tooth 43 with incomplete root canal filling and apical lesion Fig 8 X-ray control after 19 months, NAD