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Journal of LSTR Therapy (International WEB version) VOL 9: 1-6, 2010

Survival of Root Canal Pulp Tissue after Pulpitis
1,3

1,3

2

Juni Handajani , Tetiana Haniastuti , Hayato Ohshima, Etsuro Hoshino
1

1

2

Oral Ecology in Health and Infection, Anatomy and Cell Biology of the Hard Tissue, Niigata University Graduate
3
School of Medical and Dental Science, Niigata, Japan, Department of Oral Biology, Faculty of Dentistry, Universitas
Gadjah Mada, Yogyakarta, Indonesia

Abstract
The aim of this study was to demonstrate the possibility if infected and inflamed pulp tissue survived after the clinical treatment withlocal application of an antibacterial drug mixture. A total of 48 third molars, consisted with 15 teeth of pulpitis with the clinicalsymptoms of spontaneous pain, 24 teeth of pulpitis with visible pulp exposure, and 9 teeth diagnosed as necrotic pulp because of
vacant coronal pulp-chambers, was included in this study. A combination of 3 antibacterial drugs, i.e., metronidazole, ciprofloxacin,
and minocycline (3Mix), was further mixed with macrogol (M) and propylene glycol (P) and used to disinfect pulps of 47 teeth, while
the remaining one pulp was not treated as a control. 3Mix-MP was placed onto the dentin floor of cavities, or orifice of root canal,
then sealed by glass-ionomer cement and further reinforced by composite resin inlay. Seven days to 19 months after treatment, theteeth were extracted under the informed consents. They were observed by micro-computed tomography (CT) before decalcification
with 10% ethylenediamine tetraacetic acid (EDTA) solution (pH 7.0). Immunohistochemistry against Nestin and protein geneproduct (PGP) 9.5 was performed in addition to Hematoxylin and Eosin, Azan and Giemsa staining. Micro-CT revealed that, in allcases, carious lesions extended to the pulps. Clinical outcomes at the time of extraction were good in all cases without any
additional clinical symptoms. Histopathologically, in all cases, damages of pulpal tissue, such as inflammatory cell infiltration anddestruction of pulp tissue including the loss of odontoblast layers at the exposed areas, were observed as the consequence of
pulpitis. However, in all the 38 cases treated as pulpitis, both of coronal and radicular pulp-tissue survived and retained/restored thepulpal functions demonstrated by positive immunochemical reactions of Nestin and PGP 9.5. In addition, among 9 cases diagnosed
as necrotic pulp, 5 cases demonstrated that root canal pulp-tissue remained at apical one-third of root canals with a few
inflammatory cells, and Nestin and PGP 9.5 were positive in the remaining pulp-tissue, while in the remaining 4 cases, root canalchambers were entirely vacant with few scattered cells, if any. Disinfection of infected and inflamed pulp-tissue using 3Mix-MP
might result in the discontinuance of pulp destruction and the survival of pulp tissue. The present study clearly demonstrated that
pulpal tissue survived and retained/restored pulpal functions after LSTR 3Mix-MP treatment even though the cases had once
infected and inflamed with spontaneous pain, pulp exposure or partial necrosis of pulp tissue. It should be noted that, when
inflamed pulp tissue remained in root canals even the coronal pulp was destructed, it was worth first to disinfect the root canal pulps
using 3Mix-MP without removal of them, because the radicular pulp tissue could survive and restored the pulpal functions even after
once they had infected and inflamed.
Keywords: disinfection of pulps, histopathology of pulpitis and the treatment, infected dental pulp, LSTR 3Mix-MP

Introduction
Our in vitro study (1-5) demonstrated all bacteria from
infected dental pulp were fully sensitive against a combinationof
three
antibacterial
drugs,
namelyciprofloxacin,
metronidazole and minocycline (3Mix). 3mix was used as
3Mix-MP after mixed with macrogol (M) as an ointment baseand propylene glycol (P) as excellent carrier (6) of 3Mix
through dentinal tubules (7). Thus, even though 3Mix-MP wasplaced on the bottom of caries cavities over pulp chambers, it
penetrated efficiently through dentinal tubules and kill bacteria
in the pulpal lesions (7). These findings led to a new treatment
system to disinfect dental pulps without pulpectomy and topreserve the pulps (Lesion Sterilization and Tissue Repair(LSTR) 3 Mix-MP Save Pulp Therapy). In fact, 360 cases of
pulpitis with spontaneous pain, with caries lesions reaching topulps on X-ray photos, or with pulp exposure, were treated
only with 3Mix-MP medication without pulpectomy, and thepulp vitality was preserved in 95% cases. In the remaining 5% cases, the pulp sensitivity was lost, probably because thepulps had been necrotic at the time of treatment, but yet thecases were evaluated as clinical success because they had no
Accepted: November 30, 2010
Published: December 22, 2010clinical symptoms and functioned to bite without any disorders(8). In addition, histopathological evaluation of pulpitis caseswith spontaneous pains revealed that coronal pulps were
inflamed but the functions retained, indicating that after the
infective inflammation ceased, the pulp might recover
reversibly (9). Using 3Mix-MP, excellent clinical outcomes
have also been reported (8, 10-11).
In the present study, we evaluate histopatholocally whether
coronal and radicular pulps possibly survived after inflamedand disinfected using 3Mix-MP.

Materials and Methods
Patients and teeth involved in this study
Forty-eight 3rd molars from 48patients, 21-49 years old,
visited at a private dental clinic in Yogyakarta, Indonesia,
between the years of 2004 to 2009, were included in this study.
They claimed, as shown in Table 1, spontaneous pain (15cases), dental caries with pulp exposure (23 cases), and, thus,
the teeth were diagnosed as pulpitis (39 cases) according to
the conventional diagnosis. Pain on bite with vacant crownpulp chambers was also claimed, and, thus, the teeth were

Handajani et al.

LSTR 3Mix-MP to Save Pulp

diagnosed as necrotic pulp (9 cases).
Because theantagonistic teeth were lacking, those teeth were practically to
extract without endodontic treatment, those were considered
to involve in the present study under the ethical clearance
approved by the Ethic Comittee of Medical Faculty of Gadjah
Mada University, Yogyakarta, Indonesia. All the patients were
informed on the aim and the expected clinical results, as wellas the advantages and the disadvantages of intended
treatment prior to inclusion, and they all provided written
informed consent. They were treated using 3Mix-MP and,then, extracted for the histopathological evaluation certain
periods after the treatment done by a dentist in Yogyakarta.
extracted for the histopathological evaluation certain periods
after the treatment done by a dentist in Yogyakarta.
Treatment of pulpitis using 3Mix-MP
After recording clinical symptoms (Table 1), the teeth, except
for a tooth for a control evaluation, were treated withapplication of 3Mix-MP without pulpectomy or root canal
instrumentation. Pulp response was examined using an ethyl
chloride coolant (Water Ritter GmbH, Germany).
The preparation of 3Mix-MP (7-8, 10-11) were described
elsewhere. In short, after removal of the capsules or coating
materials that enclose the drug products, each of the drugs
was pulverized to fine powders using a porcelain mortar and apestle, and then stored separately in a tightly capped porcelaincontainer to prevent exposure to light and humidity. A small
amount of silica gel in a bag was placed inside the container tomaintain low humidity. The powdered drugs were used withina month of preparation. On the day of treatment, powderedciprofloxacin, metronidazole and minocycline were mixed in aratio of 1:3:3 (by volume). The vehicle, of an ointment
consistency, was prepared separately by mixing macrogol (M;Solbase, Meiji, Tokyo) and propylene glycol (P; Nikko, Japan)
in a ratio of 1:1 (by volume). The 3Mix antibiotics and MP
vehicle were thoroughly mixed to form 3Mix-MP in a ratio of
7:1 for standard consistency and, then, ball-like particles (1mm diameter) of 3Mix-MP were prepared.
3Mix-MPpreparation should be prepared and used on the day of
preparation.
The clinical treatment using 3Mix-MP (8, 10-11) were
described elsewhere.
In short, carious dentin including
softened dentin was not removed at all intentionally.
Especially, in pulpitis cases, care was taken not to damage thepulp during the preparation. Before the placement of 3Mix-MP,
the cavity was dried up using a cotton ball. In necrotic pulp
cases, a medication cavity (1mm diameter x 2mm depth) was
prepared at the orifice of root canal. The dentinal walls of the
preparation were treated with 12% EDTA, pH 7.0, for 1 min toremove the smear layer. Patients were not anesthetized withlocal anesthesia, because the above procedures do not givepain to patients. Under anesthetized conditions, dentists may
not recognize damaging the pulps and giving pain to patients.

For pulpitis cases, a 1 mm diameter ball-like particle of 3MixMP preparation was placed on the bottom of caries cavities,
not directly onto exposed pulp, and in necrotic pulp cases, aball-like 3Mix-MP was placed at the medication cavity, and,using a cotton ball, pressed to a thin layer on the cavity floor.
Then, a first layer of glass-ionomer cement (Fuji IX, GC,
Tokyo) was applied to seal 3Mix-MP with care not to express
3Mix-MP out of the cavity. The cavity was then entirely sealedwith the second layer of glass-ionomer cement. Then, awidely open-angled restoration cavity for a composite resininlay restoration was made as small in size as possible. The
wider margin areas on enamel were provided to reinforce theseal and to ensure sufficient adherence and retention of thecomposite resin-inlay restoration following etching with 35%
phosphoric acid solution. The resin-inlay, made using theClearfil composite resin (Kuraray, Tokyo) on the tooth, wascemented using the Panavia F 2.0 Estenia Cementing Kit(Kuraray, Tokyo) according to the manufacture’s manual. In
certain cases with undermined cusps, an onlay form of thecomposite resin restoration was provided. In most cases, thetreatment was completed in one visit.
Post-treatment observations were made to assess thechanges of clinical symptoms. Pulp sensation evoked by ethyl
chloride coolant was also confirmed. In addition, any pain or
discomfort on biting or chewing on the treated tooth was noted.
The clinical outcomes were defined as follows at the time ofextraction 7 days to 19 months after treatment. A “good”
clinical outcome saving pulp was defined as the lack of any
spontaneous pain, no pain on bite and the presence of pulpal
responsiveness to cold stimuli. In addition, the cases ofnecrotic pulp were evaluated as good when no clinicalsymptoms and no pain on bite were reported even if the pulpal
responsiveness was lacking, and thus, these cases wereclinically good and no further treatment was needed.
Histopathological examination of pulp tissue
Samples were checked using a Micro-CT (Elescan, Nittetsu
Elex, Osaka, Japan) for pulp exposure and dentin bridge
formation. All of the teeth were, then, decalcified with 10%(EDTA) at pH 7.0 for around 8 months, and, then, embedded
in paraffin. The serial sections of an average 4µm in thickness
were stained with Hematoxylin-Eosin (HE) for the evaluation of
pulp cell organization, with Azan for fibroblasts and collagenfibers, and with Giemsa for infiltrated inflammatory cells.
After treated with 3% hydrogen peroxide to quench theendogenous peroxidase activity, some sections were immunestained following the manufacture procedure of N-Histofine
staining kit (Nichirei Bioscience, Japan) using anti human PGP
9.5 antibodies (UltraClone, Japan) for nerve innervations, andusing polyclonal anti-Nestin antibodies (Millipore, Temecula,CA) for odontoblast function and intermediate filaments. The
applied antibodies were diluted to 1:500.

Table 1. Clinical evidence before treatment

15

Visible Pulp
expo-sure-

Spontaneous
pain
+

23

+

5
4

No. of cases

Conventionally suggested
Diagnosis
Treatment
Pulpitis
Pulpectomy

Pain on cold

Pain on bite

8

-

Pulp
response*
+

-

+

-

+

Pulpitis

+

-

-

+

-

Necrotic

+

-

-

-

-

Necrotic

Pulpectomy
Root canaltreatment
Root canaltreatment*Pulp response: examined using an ethyl chloride coolant.
Additional untreated one case was diagnosed as pulpitis with pulp exposure.
2

Handajani et al.

LSTR 3Mix-MP to Save Pulp

ResultClinical evidence before and after the treatment
Before LSTR 3Mix-MP treatment, as shown in Table 1, 38
teeth had been diagnosed as pulpitis. Among them, 15 cases
had claimed spontaneous pain but visible pulp exposure was
not observed, while other 23 cases claimed no spontaneous
pain with visible pulp exposure at the time of diagnosis.
Prolonged cold-water pain evoked in 31 cases, while, in other7 cases, the pain was slight and ceased within a few seconds.

All the 38 teeth were not painful on bite. In 23 cases having
visual pulp exposure, spontaneous pain was not claimed at thetime of treatment, although pain on cold water was claimed.
Among 9 teeth diagnosed as necrotic pulp, of which coronal
pulp chambers had opened widely and vacant, 5 teeth
revealed pain on bite, while 4 did not. Pulpal responsivenessto cold was not detected in all of 9 cases at the time ofdiagnosis.
An additional tooth, diagnosed as pulpitis with pulp exposure
without spontaneous pain, was extracted without treatment.

Table 2. Clinical evidence after treatment using 3Mix-MP
No. of cases

Diagnosed as

Spontaneous pain

Pain on cold

Pain on bite

Pulp sensitivity

15

Pulpitis

-

2*

-

+

23

Pulpitis

-

3*

-

+

5

Necrotic pulp

-

-

-

+

4

Necrotic pulp

-

-

-

-

* Slight pain for a few second.
Additional one case was not treated.

After the treatment, all patients did not claim any additional
clinical disorders until the time of extraction for 7 days to 19
months after the treatment.
As shown in Table 2, among 15 cases diagnosed as pulpitis
with spontaneous pain and extracted 7 days-10 months after
the treatment, the patients reported that pain was disappearedquite soon in all the cases after the treatment. Among 8 casesthat had claimed prolonged cold water pain before thetreatment, the pain still remained in 2 cases 2 week and 10
months after the treatment, respectively, but the pain becamevery slight only for a short period.
The clinical outcomes of 23 cases diagnosed as pulpitis withpulp exposure were also good for 7 days to 19 months after thetreatment, except for 3 cases in which pain on cold waterremained 2 weeks, 5 weeks and 5 months after the treatment,
respectively. This cold-water sensation might be ascribed by
the wide pulp exposure in these cases. However, the evokedsensation became slighter and shorter to a few seconds after
the treatment, suggesting the clinical sign was reducing tocease, probable because the exposed holes were narrowing by
the formation of calcified materials and re-calcification of soften
dentin (8). Pulpal responsiveness to cold was retained after
the LSTR 3Mix-MP treatment in all of 38 pulpitis cases.
Among 9 cases, diagnosed as necrotic pulp and treated onlywith the medication of 3Mix-MP without conventional root canaltreatment, resulted in good outcomes without any clinicaldisorders 7days to 18 months after the treatment. As shown in
Table 2, pain on bite was not observed any more in all cases.
It was striking that, in 5 cases, pulp response was restored
against the ethyl chloride coolant at the time of extraction.
Remaining 4 cases of necrotic pulp did not feel sensation
against the coolants as same as before the treatment.
Histopathological observation
As the consequence of pulpitis and LSTR 3Mix-MP treatment3

in 15 cases with spontaneous pain without pulp exposure, it
was observed at the time of extraction of the teeth after acertain period (7 days to 19 months) of LSTR 3Mix-MP
treatment, lack of odontoblast layers and infiltration of
inflammatory cells just beneath the dentin floor of caries cavity
were observed in all cases, although such a defect andhistopathological changes were rather slight (Fig. 1) eventhough all the pulps had once infected and inflamed withspontaneous pain. Except for these slight damages, almost all
pulp tissue survived and restored pulpal functions
demonstrated as the positive Nestin and PGP 9.5 immunoreactions in all cases. Giemsa staining revealed that the matrix
structure of pulp tissue in these cases retained. It was not sure
how the pulp tissue had been damaged by the pulpitis and how
LSTR 3Mix-MP treatment resulted in the repair of pulp tissue
from infective inflammation, but it was quite obvious that, at thetime of extraction, pulps were almost entirely surviving 7 days
to 10 months after LSTR 3Mix-MP treatment.
As the consequence of pulpitis with visible pulp exposure in
23 cases, pulp tissue was partly destroyed at limited areas justaround the perforation holes at the time of extraction 7days to
19 months after LSTR 3Mix-MP treatment. In the pulp tissue,
inflammatory cells were still remained in all cases, and in 17
cases inflammation was rather slight together with positive
Nestin and PGP 9.5 immuno-reactions, while in remaining 6
cases inflammatory cells had infiltrated into root canal areas
but Nestin and PGP 9.5 immuno-reactions were also positive inthese radicular pulps. The Giemsa staining revealed that thematrix structure of pulp tissue in these cases retained. Thus,
the pulp damages were considerably slight in these 23 cases(Fig. 2). Additional one case of pulpitis with pulp exposure was
not treated for a control, and inflammatory cells had infiltrated
into radicular pulp and reached to the apex areas. Despite ofthis severe inflammation, the pulp tissue was not necrotic, but
Nestin and PGP 9.5 immuno-reactions were negative.

Handajani et al.

LSTR 3Mix-MP to Save Pulp

µ-CT

Azan

HE

	
 

A

C

B

GiemsaNestinPGP 9.5

DF

E

Figure 1. A pulpitis case without pulp exposure after 10 months treated 3Mix-MP. Calcified tissue lining beneath the cavity floor
was observed (arrow). Odontoblasts (B), fibroblasts, collagen fibers, and matrix structure (C) were not damaged in coronal pulp
tissue. Nestin positive odontoblasts (E) and PGP 9.5 positive nerve innervation (F) were also observed.

µ-CTA
Giemsa

D

Azan

HE

C

B
NestinE

PGP 9.5

F

Figure 2. A case of pulpitis with exposed pulp. Odontoblasts were disarranged in radicular pulp (B). Calcification was observed in
the apical portion 19 months after treatment 3Mix-MP. Damages of fibroblast, collagen fibers and matrix structure were slight (C).
Inflammatory cells were partially remained (D), and Nestin positive odontoblasts and PGP 9.5 positive nerve innervation wereretained (E, F).
4

Handajani et al.

LSTR 3Mix-MP to Save Pulp

Azan

HE

A

B

GiemsaC
Nestin

PGP
9.5
D

E

Figure 3. A case of radicular pulp after 14 months treated LSTR 3Mix-MP. Inflammatory cells remained (C). However, fibroblastand collagen fibers were reserved (B). Nestin positive odontoblast and PGP 9.5 positive nerve innervation were retained (D, E).

Among 9 cases, diagnosed as necrotic pulps with vacantcoronal pulp chambers, 4 cases revealed that entire pulp
chamber was empty, although radicular pulps had not been
explored to avoid mechanical damages at the time of diagnosis.
It was probable that the pulp tissue had been entirely necrotic
already at the time of treatment.
However, no clinicalsymptoms claimed after the LSTR 3Mix-MP treatment. Thus,
the clinical outcomes of those 4 cases as the dental treatment
were evaluated as good. In the remaining 5 cases, root canalpulps remained at the apical one-third, with few inflammatory
cells. They were not necrotic, and positive reactions in Nestinand PGP 9.5 immuno-reactions were demonstrated,suggesting they retained/restored pulpal functions.
It was not easy to demonstrate the tissue repair such as
dentin bridge formation by the micro CT images, but as shownin Fig 1, calcified layers were observed over the remaining pulp.
Discussion
In the present study, we aimed to evaluate histopathologicalchanges of pulp tissue, which had once infected and inflamedas pulpitis, after the treatment using LSTR 3Mix-MP treatment.
However, histopathological observation needs to extract teeth,
and it is ethically impossible to extract functioning teeth after
the successful treatment. So, possible rare targets are 3rd
molars with pulpitis if the antagonistic teeth are lacking. It isalso impossible to compare the histopathological differences on
the same teeth before and after the treatment. It is also quitedifficult to get the agreement to extract teeth that have beentreated successfully and have not caused any clinical disorders
for a long time after the treatment, even if the patients once
provided informed consents. With these limitations, 48 cases
were possible to include in the present study, although theseverity of infective inflammation might be different in eachcase, and different duration from treatment to extraction might
affect histopathological images. Pulpal damages, caused by5

pulpitis, would be modified by pulpal repairs as the results ofdisinfection using 3Mix-MP.
With these limitations in mind, in the present study, weevaluated only whether pulpal tissue could survive and whether
pulp retained its functions, using Nestin and PGP 9.5
immunochemistry, at the time of extraction regardless theperiod after the treatment.
So-called irreversible pulpitis is the pulpal conditions underwhich inflamed pulp tissue had fallen into necrosis, could notsurvive and would never recovered. Even teeth with reversible
pulpitis may be going to fall into irreversible pulpitis unlesscausative bacteria of infective pulpitis are eliminated to stopand inflammatory tissue destruction. It has been reported thatthe combination of 3 antibacterial drugs (3Mix) has been
proved to kill all the types of oral bacteria (2-5, 12), including
those isolated from dentinal caries, infected pulp lesions andperiapical lesions (1, 7). Actually excellent clinical outcomes
were obtained in pulpitis treatment using 3Mix-MP without
pulpectomy or pulpotomy for the cases with spontaneous pain,with caries lesions extending to pulp chambers on X-ray photos
and/or with pulp exposure (8), which had been conventionallyconsidered the cases that needed pulpectomy or pulpotomy.
The excellent outcomes of above clinical treatment has
confirmed by following up to 2065 days after the treatment,
after much longer period than in the present study. Thus, now,
it has started to consider to save pulp tissue that had once
infected and inflamed, without removal of pulp tissue and toretain the pulp functions. The treatment is called as LSTR
3Mix-MP SavePulp (8).
It was clearly demonstrated histopathologically in the present
study, that, after LSTR 3Mix-MP treatment, infected andinflamed pulp tissue survived entirely or in part and pulp
functions retained/restored shown as positive immunochemical
reaction of Nestin (13) and PGP 9.5 (14). Since the clinicaloutcomes at the time of extraction in this study were all good
and the pulp sensitivity was restored, suggesting that inflamed
pulp tissue could be disinfected and sedated by 3Mix-MP. In

Handajani et al.

general, infective inflammation ceases after elimination of
causative bacteria, and the infiltrated inflammatory cells
disappear with time. Inflamed pulp tissue may behave thesame.
The histopathological results in the present study supported
strongly the excellent clinical results of LSTR 3Mix-MP
SavePulp therapy done by Takushige et al (8), in which thepresence of pulpal responsiveness to cold or electrical stimuli
was the only proof of survived pulp tissue without
histopathological evaluation. This clinical study together withthe results of the present study, it is strongly suggested that it
is worth to save pulps without pulpectomy even the cases of
pulpitis. However, the clinical study done by Takushige et al.
(8) has not included the cases of necrotic pulp. In general,
when coronal pulp is fully damaged, there has been no
consideration to save remaining root canal pulp, if any. As
demonstrated in the present study, root canal pulps may
possibly remain, and survive after disinfected and retain/restore
pulpal functions. It has been demonstrated that survived pulp
tissue after induced pulpitis grow up to the vacant areas of pulp
chambers in rat (15) or monkey (16). It is worth to saveradicular pulp tissue.
In addition, in the present study, cases of pulpitis and necrotic
pulp resulted in good outcomes, including the cases with fully
necrotic pulp, after LSTR 3Mix-MP treatment. Conventionally,
cases with fully necrotic pulp need root canal treatment using
root canal instrumentation and tight root canal obturation. The
present study together with other clinical studies (10-11)
indicated that, using only medication without conventional
procedures for root canal treatment, excellent clinical outcomes
have obtained. Thus, it was strongly suggested that cases of
pulpitis, regardless of absence or presence of pulp exposureand remaining pulp tissue, were worth to be treated first aiming
to save any parts of pulp tissue, since the present study
indicated that LSTR 3Mix-MP treatment could be applicable forthe cases not only for pulpitis treatment but also root canaltreatment as reported previously (10-11).
It was clearly demonstrated in the present study that thesurviving pulp tissue revealed the pulp function, showed byimmunochemical positive reactions to Nestin and PGP 9.5.
Thus, functioning odontoblasts (13), and nerve innervations(14) were retained/restored in coronal and radicular pulps acertain period after LSTR 3Mix-MP treatment. In recent
endodontic study, Banchs and Trope (17) have indicated, when
the root canal is disinfected using 3Mix and the inflammatory
conditions reversed, the pulp tissue can regenerate as theresult of revascularization. In another study conducted by Reni
and Hoshino (18), new soft tissue seems to be induced in thesterilized pulp chamber using 3Mix-MP only without
revascularization. This study also indicated that it would benecessary to keep pulp chamber sterilized to induce new pulp
tissue, and the use of 3Mix-MP is the applicable for this aim,
too.

LSTR 3Mix-MP to Save Pulp
Acknowledgment
This work was supported by a grant from Japan Society for the
Promotion of Science (JSPS) for the RONPAKU (Dissertation PhD)
program Japan.
Supported by the Grants-in-aid for Scientific Research (14406028,
and 17390500) from the Ministry of Education, Culture, Sports, Scienceand Technology, and by the grants for the Joint Research Programfrom the Japan Society for the Promotion of Science.
References
1. Kiryu T, Hoshino E, Iwaku M: Bacteria invading periapicalcementum. J Endod 1994; 20: 169-72.
2. Hoshino E, Kota K, Sato Mi, Iwaku M: Bactericidal efficacy of
metronidazole against bacteria of human carious dentin in vitro. Caries
Res 1988; 22: 280-2.
3. Hoshino E, Kurihara-Ando N, Sato I, Uematsu H, Sato. Mi, Kota K,
Iwaku M: In-vitro antimicrobial susceptibility of bacteria taken from
infected root dentine to a mixture of ciprofloxacin, metronidazole andminocycline. Int Endod J 1988; 29: 125-30.
4. Sato T, Hoshino E, Uematsu H, Noda T: In vitro antimicrobial
susceptibility to combinations lesions of human deciduous teeth. Oral
Microbiol Immunol 1993; 8: 172-6.
5. Sato T, Hoshino E, Uematsu H, Kota K, Iwaku M, Noda T:
Bactericidal efficacy of a mixture of ciprofloxacin, metronidazole,
minocycline and rifampicin against bacteria of carious and endodontic
lesions of human deciduous teeth in vitro. Microbial Ecol in Health andDis 1992.; 5: 171-7.
6. Cruz EV, Kota K, Huque J, Iwaku M, Hoshino E: Penetration of
propylene glycol through dentine. Int Endod J 2002; 35: 330-6.
7. Sato I, Ando-Kurihara N, Kota K, Iwaku M, Hoshino E:
Sterilization of infected root-canal dentine by topical application of a
mixture of ciprofloxacin, metronidazole and minocycline in situ. Int
Endod J 1996; 29: 118-24.
8. Takushige T, Cruz EV, MD. A. Asgor Moral, Hoshino E: Nonsurgical treatment of pulpitis, including those with history of
spontaneous pain, using a combination of antibacterial drug. J LSTR
Ther 2008 (International WEB version); 7: 1-5.
9. Tetiana et al. (Unpublished data)
10. Takushige T, Cruz EV, MD. A. Asgor Moral, Hoshino E:
Endodontic treatment of primary teeth using a combination of
antibacterial drugs. Int Endod J 2004; 37: 132-8.
11 Takushige T, Hoshino E: Clinical evaluation of 3Mix-MP Method in
endodontic treatment. Jap J Conserv Dent 1998; 41: 970-4.
12. Hoshino E: Bacteriological aspects of pulpitis. J Jap Assoc Dent
Science 1992; 11: 119-22 (in Japanese).
13. About I, Laurent-Maquin D, Lendahl U, Mitsiadis TA: Nestin
expression in embryonic and adult human teeth under normal andpathological conditions. Am J Pathol 2000: 157:287-95.
14. Ramieri G, Anselmetti GC, Baracchi F, Panzic, GC, VigliettiPanzica C, Modica R, Plak JM: The innervation of human teeth andgingival epithelium as revealed by means of an antiserum for protein
gene product (PGP 9.5). Am J Anat 1990; 189:146-54.
15. Komoriya T, Arai H, Kota K, Iwaku M: Study on αTCP for direct
pulp capping. Jap J Conserv Dent 1986; 29:774-80.
16. Yoshiba K, Yoshiba N, Iwaku M: Effects of antibacterial capping
agents on dental pulps of monkeys mechanically exposed to oral
microflora. J Endod 1995; 21:16-20.
17. Banchs F, Trope M: Revascularization of immature permanent
teeth with apical periodontitis: new treatment protocol. J Endod 2004;
30(4): 196-200.
18 Reni A, Hoshino E. (unpublished data).

Correspondent Author:
Professor HOSHINO Etsuro
Oral Ecology in Health and Infection,
Niigata University Graduate School of Medical and Dental Sciences
Gakkocho-dori 2, Chu-oh-Ku, Niigata 951-8514 Japan
Fax: +81 (0)25-227-0806; Tel: +81 (0)25-227-2838; e-mail: hoshino@dent.niigata-u.ac.jp6