CHAPTER THIRTEEN
The Symptomatic Treatment of Dental Decay
I. Introduction
II. Removal of Infection
A. Caries Debridement
B. Indirect Pulp Capping
C. Pulpal Sterilization
III. Evaluation of Symptomatic Dental Treatment
A. Cost of Symptomatic Treatment
B. Dental Health Resulting from
Symptomatic Treatment
C. Symptomatic Treatment vs Preventive Treatment
l. Karlstad studies
2. Ypsilanti, Michigan studies
IV. Summary
INTRODUCTION
The treatment of dental decay has been concerned primarily with the physical removal of the carious tooth material followed by the replacement of the lost tooth substance, either with an inert restorative material or if the tooth was extracted, with an artificial tooth. This is a sound bacteriological approach, regardless of whether one is treating according to the nonspecific plaque hypothesis or the specific plaque hypothesis. In the former case the carious tooth substance is removed because the decay ultimately will progress into the pulp, thereby causing pain and jeopardizing the future of that tooth in the mouth. In the case of the specific plaque hypothesis, there is the added concern that the carious lesion will serve as a focus of infection that can seed other teeth in the mouth with S. mutans and other odontopathogens.
簡介
治療齲齒的方法主要是移除蛀牙的區域，接著將失去的牙齒物質以填補的方法、或是拔牙後以假牙取代。從細菌學的觀點來看，不論操作者是依據非專一性牙菌斑假說(nonspecific plaque hypothesis)或專一性牙菌斑假說(specific plaque hypothesis)，這種去除齲齒的方法都是合乎理論的。若是根據非專一性牙菌斑假說，蛀牙的齒質需被移除的理由，是為了避免進一步產生疼痛，以及避免危害這顆牙齒在口中的未來。而根據專一性牙菌斑假說的理論，齲齒患處則被認為是感染的來源，可能會將S.mutans以及其他口中致病菌傳染到其他顆牙齒上。
Great technological improvements in the physical properties of dental materials and in painless and efficient ways of removing the carious tissue from the tooth have occurred in the 20th century. Yet these improvements have had no effect on the incidence of dental caries. If it were not for the accidental discovery of fluoride's protective role against dental decay, the magnitude of decay in societies eating high proportions of foods sweetened with sucrose would be catastrophic. As it is, dental caries is regarded as being universal in man.
在二十世紀，牙科材料在物理性質方面有很大的進步，而且開始能以無痛且有效的方式將蛀牙移除，可是這些進步卻對蛀牙的發生率沒有幫助。如果不是偶然間發現了氟對於蛀牙的預防效果，在現今高蔗糖飲食的社會裡，蛀牙發生的量將會大到像場災難。因此，蛀牙被視為全人類共通的問題。
Why hasn't dental science been able to curtail the incidence of dental decay? Why haven't there been other advances commensurate with the efficacy of water fluoridation? To begin to answer these questions one has to examine the basic premise regarding caries etiology. The prevailing view since Miller's time has been that bacteria cause dental decay by their accumulation on retentive sites on the tooth surfaces. To control caries, therefore, one must suppress these accumulations. This has proved to be most difficult, considering the ability of the bacteria to attach on the tooth surfaces and to rapidly proliferate. Accordingly, preventive tactics based upon the nonspecific plaque hypothesis have been unsuccessful. But what would be the strategy and tactics for prevention if decay resulted from the dominance in the plaque of certain acidogenic organisms such as S. mutans and lactobacilli. Treatment would be limited to those individuals in whom a diagnosis of infection with these organisms could be made. Until recently there has not been enough information for treatments according to the specific plaque hypothesis to be directed effectively. In this and in Chapters 14-20, various treatment strategies and tactics, based upon both the nonspecific and specific plaque hypotheses, will be discussed. The mechanical debriding of tooth surfaces will be described first, as this represents the dominant modality of treatment in clinical dentistry.
為什麼目前牙科的技術仍無法降低蛀牙的發生率？是否有其他和飲水加氟一樣有效的方法？要回答這些問題前，必須先由齲齒發生的原因來檢視。從Miller時期開始，普遍的觀點認為蛀牙是來自於牙齒齒面上細菌的累積。因此，要控制蛀牙，就必須抑制細菌在牙齒上的累積。但這是很難做到的，因為細菌具有附著在牙齒上的能力，並且可以很快速的繁殖。因此，依據非專一性牙菌斑假說所提出的預防性措施是不成功的。但是，如果蛀牙是因為某些特定的口內細菌，如：S.mutans或是Lactobacilli所造成，那什麼才是有效的預防措施呢？首先必須能正確診斷出哪些病人已感染某些特定菌種，之後才能發展出治療的方法。但直到目前為止，根據專一性牙菌斑假說進行治療的資料仍不足以證明有效。在本章以及14-20章將以非專一性牙菌斑假說和專一性牙菌斑假說為基礎，討論不同的治療方法。首先會討論在牙齒表面進行機械式清創(mechanical debriding of tooth surface)的方法，這也是目前臨床牙醫界最常用的方法。
REMOVAL OF INFECTION (Symptomatic Treatment)
Patients usually appear in the dental office when symptoms are present. This necessitates a symptomatic treatment regimen which invariably includes the physical removal of decay from the tooth, or the tooth from the mouth. This removal of decay is also required by a specific infection hypothesis, as the carious tooth can serve to infect other teeth, as was shown in studies with the artificial fissure in which labelled strains of S. mutans spread from a discrete tooth location to colonize adjacent teeth (See "S. mutans Colonization" in Chap. 6).
去除感染(根據症狀的治療)
病人通常是因為有症狀而求診，所以我們必須依症狀做不同的治療，例如將牙齒上的齲齒移除，或是將牙齒由口內移除。因為蛀牙的牙齒會對其他牙齒造成感染，因此在專一性的感染假說(specific infection hypothesis)中，齲齒的移除也是必須的，像是在實驗中，若在人工製造的溝隙內放入標記過的S. mutans，會發現細菌會散播至鄰近的牙齒上(見第六章的"S. mutans Colonization")。
Caries Debridement
The extraction of a tooth is a quick and efficient means of eliminating an infected reservoir, but ideally should be a last resort because of the functional morbidity that it introduces into the dentition. The usual means of removing decay is by a combination of high speed drills and hand instruments. The tooth, thus debrided, is restored with a suitable dental material so as to achieve a functional and aesthetic clinical result. But how effective is this debridement in removing a S. mutans infection from these teeth or from the dentition? Loesche et al. have examined pooled approximal and fissure plaque as well as saliva in rampant caries patients before and after the delivery of the required dental treatment, i.e., placement of restorations and extraction of teeth. The levels of S. mutans were decreased compared to pretreatment values three to five fold in plaque and ten fold in saliva immediately after the completion of the polishing procedure (Table 13-1). However, one week later the fissure and salivary levels of S. mutans increased. The dental treatment had minimal effect on the proportions of S. mutans in the plaque (Table 13-1). This demonstrated that the standard method of caries treatment leaves the teeth still infected with S. mutans, a fact which might account for recurrent caries on some teeth and continued caries activity in many patients. What seems indicated are additional means of suppressing S. mutans during this mechanical debridement procedure (See "Fluoride-antimicrobial effects" in Chap. 18).
齲齒清創 Caries Debridement
拔牙是一個快又有效去除感染的方法，但是通常是最後一步，因為拔牙會造成齒列功能上的缺失。最常用來移除齲齒的方法是使用高速磨牙機(high speed drills)和手動器械(hand instruments)。清創完成的牙齒，會用合適的牙科材料進行復形，以回復臨床上的功能及美觀。但是，這樣的清創，對於受感染的牙齒或齒列其移除S. mutans的效果又是如何呢？Loesche et al曾研究猛爆型齲齒病人在接受牙科治療（例如：補牙或拔牙）前後，牙齒鄰接面和溝隙面的牙菌斑及唾液中S. mutans的量。結果發現在剛完成治療時，牙菌斑中的S. mutans的量會下降3-5倍，唾液中S. mutans的量會減少十倍(表13-1)。但是在一週後，溝隙和唾液中的細菌量都上升了，牙科治療對於牙菌斑中S. mutans所占比例的影響很小(表13-1)。這證明了標準的齲齒治療使牙齒仍受S. mutans的感染，這可能也說明了為何有些牙齒會有續發性齲齒，而有些人會一直蛀牙。這表示在對齲齒進行機械性的清創過程中，需要在加入某些步驟以減低S. mutans的量 (請見第十八章"氟化物的抗菌作用")。
The heat of friction generated by drilling against the tooth requires an air-water coolant to be used. The resulting aerosol has elevated levels of bacteria, but this appears to pose no threat to the medical health of the patient or the dentist. The bacterial density of the aerosol is highest within the mouth and declines extraorally with distance from the drilling site. The bacterial composition of the aerosol that is sprayed on the other teeth can be high in proportions of S. mutans. In the experiment presented in Table 13-2 a saliva ejector, which was connected to a high-power suction source and which had a bacterial filter positioned in line prior to the suction, was placed on the occlusal surfaces on the side opposite to the tooth to be drilled. Prior to drilling, only a few bacteria were aspirated by the suction device. When the tooth was being excavated, the bacterial count increased 100,000-fold and contained high proportions of S. mutans. The same pattern was observed in regard to the proportions of S. mutans deposited on a filter held in the vicinity of the operator's face.
因為鑽牙時產生的熱需要空氣-水冷卻，所造成的氣霧(aerosol)裡細菌的量會隨著上升，但這似乎對病人或牙醫沒有危害。在口內的氣霧中細菌濃度是最高的，隨著離鑽牙區的距離增加而下降。散佈到其他牙齒上的氣霧中，其細菌組成中可能含有高濃度的S. mutans。表13-2是對吸唾管中細菌的含量進行檢測，將吸唾管放置於鑽牙區另外一邊牙齒的咬合面上，並在和強力抽吸裝置(high power suction)連接之前，裝置一個細菌的濾器。在還沒鑽牙前，吸唾管中細菌的量很少，但當開始清除蛀牙時，吸唾管中細菌的量增加了100,000倍，而且含了高比例的S. mutans。同樣的情況也可在牙醫師面罩上的過濾器周圍被觀察到。
This raises the possibility that the debriding procedure can serve to inoculate other teeth in the patient's mouth as well as the attending dental personnel with S. mutans. This would be of concern only if S. mutans is a specific dental pathogen. The likelihood of the operator becoming infected is low when one considers the great difficulty associated with the implantation of in vitro-grown S. mutans in humans (See "S. mutans Colonization" in Chap. 6). However, the colonization of the patient's teeth by his indigenous S. mutans could be another matter, especially considering that the teeth are pulsed with about 6,000 S. mutans per minute, and that these S. mutans cells have already proved to be capable of living on the teeth of this particular host. This potential seeding can be prevented or minimized by the usage of high speed suction in the immediate vicinity of the drilling site and/or the usage of the rubber dam.
這表示由清創(debriding)這個步驟，而造成S. mutans傳播到口中其他牙齒或到牙科人員身上的可能性增加了，若S. mutans為會引起牙齒疾病的特定細菌時，這項發現才有意義。因為in vitro培養的S. mutans很難在人體存活(見第六章"S. mutans Colonization")，因此操作者受到感染的機會很低。然而，在一個原本就有S. mutans的宿主口中傳播S. mutans又是另當別論，尤其是當這顆牙每分鐘被S. mutans衝擊6000次，而且這隻S. mutans又已被證明可在此宿主生存時。這種潛在的感染，可以藉由在鑽牙處使用強力抽吸裝置，或是橡皮防濕障的使用來避免。
Indirect Pulp Capping
The debriding of the carious lesion continues until all the soft, infected dentin is removed, except in those instances where complete removal might cause pulpal exposure. In this situation the clinician temporizes by placing a dressing, usually of calcium hydroxide, over the residual carious dentin in a procedure known as indirect pulp capping. The alkalinity of the calcium hydroxide causes a hardening of this dentin, but more importantly, stimulates the odontoblasts lining the wall of the pulp to lay down a layer of secondary dentin in the vicinity of the lesion. Months later the clinician can reenter the tooth and remove the residual carious dentin with minimal risk of pulpal exposure. The necessity of this reentry process has been debated, as in most instances the teeth are asymptomatic and there is no x-ray evidence of extension of the decay into the pulp. Some argue that any remaining bacteria can continue to grow, possibly obtaining nutrients by diffusion from the pulp or by leakage about the restoration, and thereby remain a constant threat to the vitality of the tooth.
間接覆髓術 (Indirect Pulp Capping)
一般蛀牙的清除會將所有軟化的、受感染的牙本質移除，除了在某些情況之下，完全的移除會造成牙髓的暴露。在這種情況下，牙醫師會在剩餘的蛀牙區放上一個暫時的敷藥(通常是氫氧化鈣)，這個術式為間接覆髓術(indirect pulp capping)。氫氧化鈣的鹼性會造成牙本質的硬化，但更重要的是，可以刺激牙髓腔周圍的牙本質母細胞產生二級牙本質(secondary dentin)。經過數月後，醫師可以重新將剩餘的蛀牙清除乾淨，而減低牙髓暴露的機率。到底需不需要再重新進入，將剩餘的蛀牙清除仍有爭議，因為大部分牙齒通常是無症狀的，而且X-ray上也沒有顯示蛀牙區有擴大到牙髓的跡象。也有些人質疑殘留的細菌也許可以藉由從牙髓滲透作用獲得養分、或由復形物的裂縫獲取營養，進而持續生長，並對牙齒的活性造成危害。
Several studies have sought to determine the viability of organisms left behind in the carious dentin after calcium hydroxide treatment. The teeth were reentered and the softened dentin was deposited in broth media without any regard for quantitative enumeration or anaerobic procedures. In most instances, the residual dentin was sterile. This is not surprising considering that calcium hydroxide at a pH of 11 to 12 would cause cell death of most bacteria, especially those with a pH optima below 7, as would be characteristic of the aciduric organisms found in the dentinal lesion.
在放置氫氧化鈣後，殘存在蛀牙區的微生物是否仍具有生存能力，有些實驗對此進行了研究。在不考慮定量或無菌的情況下，重新進入牙齒並取出軟化的牙本質加以培養，發現大部分都是無菌的。這並不令人意外，因為大部分牙本質蛀牙內發現到的細菌為耐酸性的，適合生活在pH值小於7的環境，而pH值為11至12的氫氧化鈣會使大部分這類的細菌死亡。
The extent of the killing effect of calcium hydroxide in situ was determined in the following experiment. Carious teeth with extensive dentinal involvement, which did not encroach upon the pulp, were opened and the occlusal portion of the carious dentin was removed (Fig. 13-1A and 1B). The remaining carious dentin on one side was then excavated with hand instruments (Fig. 13-1C) and thereafter weighed, dispersed, serially diluted and cultured anaerobically. The dentin left in situ was covered with a layer of either calcium hydroxide, or zinc oxide eugenol (Fig. 13-1E) or by a wax bandage (Fig. 13-1D) before the cavity preparation was filled with a temporary cement. The wax bandage served as a control, as the wax exerted no antimicrobial activity and acted as a barrier against any antimicrobial activity on the part of the temporary cement filling.
以下的實驗則是研究在放置氫氧化鈣原位(in situ)處其殺細菌的範圍。實驗選取有大量牙本質蛀牙卻尚未侵犯至牙髓的牙齒，將靠近咬合面的蛀牙移除後(圖13-1A和1B)，剩餘的蛀牙以手動器械刮除後(圖13-1C)，將蛀牙秤重、分散、序列性稀釋，然後進行無菌培養。剩下的牙本質則用氫氧化鈣或ZOE(圖13-1E)或蠟條(was bandage)覆蓋後(圖13-1D)，再用暫時性的黏著劑充填。因為蠟不會產生抗菌的能力，而且也可以阻擋暫時性黏著劑產生的抗菌力，因此，此實驗將蠟條視為控制組。
Either one or five months later, the teeth were reentered and the remaining half of the carious dentin was removed (Fig. 13-1F) and cultured as before. The treated teeth exhibited a 95 percent reduction in bacterial counts, whereas in the control teeth, the counts increased by about 100 percent (Table 13-3). No control teeth were sterile, whereas 26 of the 80 treated teeth were sterile (Table 13-3). Thirteen of 20 control teeth showed an increase in bacterial counts, whereas an increase occurred in only five of 86 treated teeth. In 55 treated teeth the bacterial levels decreased.
經過一個月和五個月後，再重新進入牙齒，並移除剩下的蛀牙(圖13-1F)，並照之前的程序進行培養。治療過的牙齒細菌量降低了95％，而控制組則增加了100％(表13-3)。控制組的牙齒全都是有菌的，但治療過的牙齒80顆中有26顆是無菌的(表13-3)。控制組的牙齒中，20顆牙齒裡有13顆細菌是增加的，但治療過的牙齒86顆中只有5顆的細菌增加，而剩下55顆則是減少的。
The surviving bacteria in the treated teeth could have been bacteria that were resistant to calcium hydroxide and zinc oxide eugenol, or more simply, bacteria that did not contact these agents because they were in the core of the residual dentin. In this regard, the amount of dentin left behind in these experiments was considerable compared to that left behind in the actual clinical pulp capping procedure. This difference is illustrated in Figure 13-1C where the black bottom layer represents the thickness of the dentin that would normally be left in the indirect pulp capping procedure and the speckled area, the additional amount left behind in these experiments. Thus if the clinical procedure had been followed, it is reasonable to expect that even more bacteria would have been killed. If this is so, then reentry to remove the residual carious dentin after capping with either calcium hydroxide or zinc oxide-eugenol may not be necessary, if the final restoration maintains its seal and the tooth is asymptomatic.
在治療過的牙齒中，那些存活下來的細菌之所以沒有死亡，可能是對氫氧化鈣或ZOE有抵抗力，也可能是因為它存在於蛀牙的中心，而不與這些物質接觸。如此一來，比較實驗時和臨床上操作間接覆髓術時，到底各留下多少的牙本質，這點差異是必須考慮在內的。兩者間的差異可見圖13-1C：黑色的底層是間接覆髓術會留下的牙本質，而斑點處則是實驗中多留下的牙本質。如果實驗是按照臨床的步驟去操作，可以合理的推測將會有更多的細菌被殺死。如果真是這樣，如果最後的復形物有好的密封性，而且牙齒是沒有症狀的，那麼在放置氫氧化鈣或ZOE後，可能就不需要再重新進入牙齒，移除剩餘的蛀牙了。
Pulpal Sterilization
When decay extends into the pulp, an acute inflammatory response results that inevitably leads to pulpal death, frequently to abscess formation at the tooth apex and rarely to a bacteremia that results in subacute bacterial endocarditis. Treatment is either extraction or root canal therapy with systemic antibiotics such as penicillin given if acute symptoms are present. Root canal therapy is to be preferred, as it retains the tooth in situ and has an extremely high success rate, i.e., greater than 95 percent.
牙髓消毒 Pulpal Sterilization
當蛀牙延伸到牙髓時，急性的發炎反應最後必然會造成牙髓的死亡，接著經常產生根尖膿瘍或是極少見的亞急性細菌性心內膜炎(subacute bacterial endocarditis)。治療的方法為拔牙或是根管治療配合系統性的給予抗生素，例如：在有急性症狀時給予盤尼西林。因為根管治療可以保留牙齒，並且擁有高於95%的成功率，所以傾向選擇根管治療。
Because of the concern over periapical infections and because of the seriousness of subacute bacterial endocarditis, the endodontist seeks to sterilize the root canal before it is filled. He/she mechanically debrides the canal surface, irrigates with potent protein denaturants, such as paraformaldehyde, camphorated monoparachlorophenol and hydrogen peroxide during these debriding procedures, and then between treatment visits, places a tapered paper point saturated with one of the above medicaments into the canal. The sterility of the canal is tested by aseptically placing a sterile paper point into the full length of the canal and then placing this point into a broth medium which is incubated aerobically. Any bacterial growth means that the canal remains contaminated and should not be filled. Two or three successive negative cultures indicate that the canal is sterile and can be filled.
因為要避免根尖的感染以及嚴重的亞急性細菌性心內膜炎的發生，牙髓病科醫師在進行根管充填前，必須先將根管進行消毒。醫師會以機械性的方式進行根管的清創，並在清創過程中使用強效的蛋白質變性劑進行沖洗，例如：多聚甲醛(paraformaldehyde)、CMCP(camphorated monoparachlorophenol)和過氧化氫(H2O2)，在每次治療間，在根管內置放浸滿上述藥劑的紙針。在無菌的環境下將無菌的紙針放到根管全長處，再將紙針拿出、放入培養基中進行無氧培養，以測試根管內是否達到無菌。只要有任何的細菌被培養出來，即表示根管內不是無菌的，就不進行根管的充填。必須培養出二到三次是陰性的結果時，才表示根管內是無菌，這時才可以進行充填的動作。
This culturing procedure is fraught with conceptual and technical problems and has been the subject of disagreement among endodontists. The method is so sensitive that the presence of a single bacterial cell could result in a positive culture. This single cell could arise from the canal itself, from contact with any part of the cavity preparation, from the air, from nonsterile instruments, from a nonsterile paper point or from contact with the operator. Thus it is possible to obtain false-positive cultures. There is also no way to determine whether the positive culture reflects contamination at the apex or at the coronal opening to the canal. Contamination at the latter site is rather inconsequential, given its long distance from the apex and the antimicrobial nature of the filling cement. Also, by this procedure there is no way to quantitate the level of residual bacteria in the canal. A microbial load of less than 1000 may have no biological significance, whereas a load greater than a million might require prompt retreatment. Finally, false negatives can arise if the paper point adsorps within the canal any residual medicaments such as the formaldehyde and/or phenolic compounds used to sterilize between visits. Several investigators have shown that paper points can become contaminated with these chemicals to the extent that they inhibit bacterial growth if they are placed on an agar medium which had been previously inoculated with bacteria. If such a point containing medicaments at its coronal end and bacteria at its apical end is inoculated into broth, it is possible that the medicaments could diffuse into the broth and inhibit bacterial growth giving rise to a false negative. False negatives can also arise if the paper point cannot gain access to an area of the root canal which harbors bacteria, i.e., the apical aspect of the canal, lateral canals, etc.
這樣的培養過程伴隨著許多概念上與技術上的問題，所以無法受到牙髓病科醫師的認同。這個方法靈敏度太高，只要存在一個細菌，結果就會是陽性。而這個細菌可能來自於根管本身、窩洞的修形、空氣、非無菌的器械、非無菌的紙針或是和操作者的接觸，因此獲得的結果可能是偽陽性。此外，我們也無法確定到底陽性結果代表的是來自於根尖、或是來自於根管開口的感染。若是來自於根管開口的感染，則較不重要，因為位置離根尖的距離較遠，且封填的材料具有抗菌力。另外，這個步驟也無法將根管內殘餘的細菌進行定量，當microbial load低於1000可能沒有生物性上的差異，但若細菌量大於1,000,000，可能需要重新治療。再來，如果紙針吸附了根管內殘存用於殺菌的藥物，如：每次治療間放置在根管內的藥物(甲醛或酚化合物)，就可能會出現偽陰性的結果。有些學者研究了這些受到藥物汙染的紙針，若將這些紙針置放在有細菌的培養皿上，結果發現這些紙針受到藥物汙染的程度已足以抑制細菌的生長。若紙針在根管的開口處沾上了藥物，而在根尖處是有細菌的，這些藥物可能會藉由滲透作用達到根尖處，而抑制細菌的生長，導致偽陰性的結果。另外，若紙針無法到達細菌存在的地方，像是根管的最根尖處、側枝根管等地方，也可能發生偽陰性的結果。
These inadequacies of the paper point culturing technique suggest that the information provided by it is of questionable clinical value. This is borne out by numerous investigations which indicate that the bacteriological status of the canal, as determined by the paper point technique, has a minimal effect upon clinical success. In teeth filled after a positive culture, success occurred in 76 to 86 percent of the cases, whereas in teeth filled after a negative culture, success was obtained in 82 to 96 percent of the cases. Thus a presumably sterile canal was associated with about a 10 percent higher success rate. Clearly some factor other than sterility was achieved by therapy, which accounted for the high degree of healing. This could be a reduction in the bacterial load in the canal from those which caused symptoms to those which could be handled by the host's defense mechanisms. This possibility was examined for by Lindemann and Loesche in the following study.
這些利用紙針進行培養的技術並不適當，因此實驗結果所提供的資訊其臨床價值並不高。許多調查也指出，利用紙針技術決定的根管內細菌量，其對於臨床成功率的影響很微小。陽性反應的根管在充填之後，成功率有76%到86%，而陰性反應的根管在充填之後，成功率為82%到96%。因此，假設為無菌的根管，其治療的成功率只約高出10%。很明顯的，這表示治療除了能達到無菌的狀態以外，還能產生其他的因子以提高根管本身的痊癒程度。可能是根管內細菌量的降低，使宿主可用本身的防禦機制來避免症狀產生。這個可能性將由以下Lindemann和Loesche的實驗來驗證。
Forty non-vital teeth in which the pulp chamber had not been exposed to the oral cavity were chosen for study. The teeth were isolated with a rubber dam and disinfected prior to opening into the canal. A 0.1 ml aliquot of a bacterial transport medium was placed into the canal and this was introduced into all areas of the canal by instrumenting for 45 seconds with a sterile endodontic file. The file was withdrawn and the blade end cut off and cultured using a quantitative anaerobic procedure (See "Serial Dilutions" in Chap. 2). Two sterile paper points were then consecutively placed into the canal for one minute and then inoculated into broth which was incubated either aerobically or anaerobically. This procedure was followed at each of three treatment visits prior to the instrumentation of the canal.
總共選取40顆已喪失活性、但牙髓腔未暴露在口腔內的牙齒，利用橡皮防濕障將這些牙齒進行隔離與消毒，之後進行髓腔開擴。接著，將0.1 ml的細菌帶入根管中後，用消毒過的根管銼針(file)將細菌帶入根管內的每個面，45秒後將銼針取出，並將末端切下進行定量的無菌培養(見第二章”序列性稀釋”)。另外，連續在根管內放入兩支消毒過的紙針，經過一分鐘後取出，分別進行無氧及有氧的培養。以上這些步驟會在每次開始根管治療前進行。
The teeth were randomly assigned to one of the following four treatment regimens: in Group I, tap water was used as the irrigating fluid and an unmedicated sterile cotton pellet was placed in the pulp chamber prior to closure; in Group II, tap water was used to irrigate and a dry cotton pellet containing formocresol was placed in the pulp chamber; in Group III, Chlorox® was used to irrigate and an unmedicated pellet was placed in the pulp chamber; in Group IV Chlorox® was used to irrigate and a pellet containing formocresol was placed in the pulp chamber. All teeth were sealed with Cavit® as a temporary restoration.
這些牙齒被隨機分成四組：第一組使用自來水做為沖洗液並在髓腔內放置不含藥劑的棉球；第二組使用自來水做為沖洗液並在髓腔內放置含有甲醛甲酚(formocresol)的棉球；第三組使用Chlorox®做為沖洗液並在髓腔內放置不含藥劑的棉球；第四組使用Chlorox® 做為沖洗液並在髓腔內放置含有甲醛甲酚(formocresol)的棉球。所有的牙齒都以Cavit®做暫時的復形。
The bacteriological findings are presented in Table 13-4. In the initial cultures the median anaerobic bacterial counts outnumbered the median aerobic counts by about 100 to 1, clearly demonstrating that in the majority of the teeth the pulpitis was due to an anaerobic infection. Instrumentation and irrigation with water (Group I) did not reduce the number of organisms in the canals and actually was associated with a significant increase in the aerobic flora at the second visit. Instrumentation and irrigation with Chlorox® (Group III) decreased the anaerobic count, but selected for the aerobic organisms. Instrumentation, irrigation and medication with formocresol (Groups II and IV) caused a significant decrease in the anaerobic counts and a marked 10 to 100-fold decrease in the aerobic counts. As most clinicians medicate between visits with agents as potent as formocresol, the results obtained in Groups II and IV probably reflect the bacteriological status of most treated root canals.
All teeth were filled after three treatment visits, provided the tooth was asymptomatic, dry and prepared to receive the filling material. Thus teeth treated with formocresol and having a cultivable bacterial load of less than 200 organisms, appeared clinically to be no different than the teeth irrigated with water, given no medication and having a cultivable bacterial load of 100,000 organisms. This is a surprising finding and indicates that bacteriological cultures are of little value in determining when to fill a root canal.
表13-4為測試出來細菌的結果，最一開始的培養基中顯示，厭氧菌的數量遠大於好氧菌，約為100：1，表示大多數的牙髓炎是由於厭氧菌感染引起的。使用自來水沖洗(第一組)並不能降低根管內微生物的數量，而且和第二次治療時根管內好氧菌的數量增加有關。使用Chlorox®為沖洗液(第三組)可以使厭氧菌的數量減少，但卻會對好氧菌進行選擇。使用甲醛甲酚(第二、四組)可顯著的降低厭氧菌的數量，好氧菌的數量也可以減少10至100倍。許多醫師會在治療期間放置如同甲醛甲酚有效的藥劑，但事實上根管內的變化為何，我們可由第二和第四組看出。在經過三次治療後，若沒有症狀且根管已為乾燥的，所有的牙齒將會進行根管充填。在此發現，使用甲醛甲酚治療的牙齒其細菌量小於200，而只用清水沖洗的牙齒其細菌量大於100,000，但兩者間在臨床上並沒有顯著差異，這是一個令人驚訝的發現，表示其實細菌量的多少與何時進行根管充填是沒有相關的。
The availability of results from the paper point cultures and the quantitative cultures on the same teeth permitted an evaluation of the paper point procedure. Sixty of 93 paper points incubated aerobically and 74 of 111 incubated anaerobically were positive, whereas all cultures were positive by the quantitative procedure (Table 13-5), with the counts ranging from 200 to l00,000,000 organisms per canal. There was a tendency for the paper point cultures to be negative at counts less than l0,000 and positive at counts greater than l0,000. However, only in those tubes incubated aerobically in which the inocula contained ten million or more organisms did the paper point cultures correctly reflect, in all instances, the positive bacteriological status of the canal (Table 13-5). At all other bacterial levels the paper point cultures exhibited from 14 to 50 percent false negatives.
因為可以獲得利用紙針做細菌培養和細菌數定量的結果，讓我們可以對紙針的使用程序進行評估。當進行定量程序時，每根紙針上都有細菌的，而在有氧環境下的培養結果，93根紙針中有60根是陽性的；而在無氧環境下，111根紙針中有74根是陽性的(表13-5)，每個根管內細菌數量多少由200個到100,000,000個。當細菌量小於10,000時，培養出結果為陰性的可能性較大；而當細菌量大於10,000時，結果為陽性的可能性較大。然而，只有在細菌量大於一千萬時，紙針培養程序才會正確的反映出陽性結果(表13-5)。當細菌量不在這個範圍內時，約14%到50%的結果為偽陰性。
This unreliability of the paper point culturing procedure, plus the lack of correlation between bacterial levels (Table 13-4) and clinical appearance at the time of filling a root canal, argues against routine bacteriological cultures in endodontic therapy. The usage of intra-canal medication with formocresol or similar compounds between visits has a decided antimicrobial effect and should be encouraged. Diagnostic culturing should be performed when a tooth is acutely symptomatic and/or unresponsive to instrumentation.
由於紙針培養程序的結果不夠準確，而且細菌量的多少和決定臨床上是否進行根管充填間並無關係(表13-4)，因此，根管治療是否需要常規細菌的培養是有爭議的。在每次療程中間於根管內放置甲醛甲酚或類似的藥劑的確有抗菌的效果，且是被鼓勵的。而當牙齒是有症狀且/或對清創無反應時，才需進行診斷性的細菌培養(diagnostic culturing)。
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