• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.366-374
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• 1996

The purpose of this study was to investigate whether D-myo-inositol-l,2,6-trisphosphate (PP56) can effectively antagonize vasoconstriction caused by neuropeptide Y in the dental pulp, and to understand involvement of neuropeptide Y in the regulation of microcirculation in the dental pulp with the aim of elucidating neurogenic inflammation. Experiments were performed on 7 cats anesthetised with sodium pentobarbital, and neuropeptide Y and a neuropeptide Y antagonist PP56 were injected close intra-arterially into the dental pulp. The probe of laser Doppler flowmeter was placed on the buccal surface of ipsilateral canine teeth to the drug administration and pulpal blood flow was measured. Intra-arterial injection of neuropeptide Y (1.3-$2.0\;{\mu}g$/kg) resulted in pulpal blood flow decrease of $37.73{\pm}5.73%$(mean${\pm}$SEM) (n=9). Intra-arterial injection of PP56(0.3 mg/kg) alone changed pulpal blood flow little by 1.03 % reduction. The effect of neuropeptide Y in the presence of PP56 resulted in significantly less decreases in pulpal blood flow ranging from $27.17{\pm}5.37$ to $16.63{\pm}3.48%$ from control as compared with neuropeptide Y alone(n = 13). In effect, PP56 attenuated pulpal blood flow caused by neuropeptide Y. Results of the present study have provided evidences that a non-peptide PP56 is capable of antagonizing vasoconstriction caused by neuropeptide Y in the feline dental pulp. In addition, they show functional evidences that neuropeptide Y plays an active role in modulating the microcirculation of the dental pulp.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.193-201
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• 2000

Prostaglandins (PGs) and Leukotrienes (LTs) have been implicated in the genesis of pulpal and periapical inflammation. In this study, the relationships among $PGE_2$, 6-keto-PG $F_1{\alpha}$ (a stable metabolite of $PGI_2$) and $LTB_4$ concentrations in inflamed pulp and periapical lesions were discussed. Pulp tissue were obtained in routine endodontic treatment and periapical lesions in periapical surgery after clinical diagnoses were made. These specimens were divided into four groups as normal pulp group (Control group), acute pulpitis group, chronic pulpitis group, and periapical lesion group. Pulp tissue and periapical lesions were stored in liquid nitrogen. The concentration of $PGE_2$, $PGI_2$ and $LTB_4$ were measured with ELISA. The data were analyzed by one-way ANOVA. Significantly higher levels of $PGE_2$, 6-keto-PG $F_1{\alpha}$ a and $LTB_4$ were found in acute pulpitis group than chronic pulpitis group and periapical lesion group(p<0.05). Periapical lesion group showed significantly higher mean concentrations of $PGE_2$ and $LTB_4$ than chronic pulpitis group. In control and chronic pulpitis group, significant higher levels of $PGI_2$ than $PGE_2$ and $LTB_4$ were found. These results suggested that the high levels of $PGE_2$ and $LTB_4$ in periapical lesions may be due to rich endothelium., fibroblast and lymphocyte known as the main producers of $PGE_2$ and $LTB_4$. $PGI_2$ may be thought to one of the most abundant PGs in normal pulp tissue.

• Journal of Periodontal and Implant Science
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• v.54 no.2
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• pp.65-74
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• 2024

Purpose: This longitudinal cohort study aimed to evaluate the relationship between osteonecrosis of the jaw and pulp and periapical disease in patients who were administered bisphosphonates. Methods: Using data from a nationwide cohort, we examined the association among dental caries, pulp and periapical disease, and osteonecrosis of the jaw in women aged >50 years who received bisphosphonates for more than 1 year between 2002 and 2015. Because of ambiguities in the diagnosis of osteonecrosis of the jaw in population-based data, we operationally defined and categorized the condition into established and potential osteonecrosis of the jaw. Results: Pulp and periapical disease significantly increased the development of both established and potential osteonecrosis of the jaw (hazard ratio, 2.21; 95% confidence interval, 1.40-3.48; and hazard ratio, 2.22; 95% confidence interval, 1.65-2.98, respectively). Root canal treatment did not have any influence on the development of osteonecrosis of the jaw. Conclusions: Pulp and periapical disease may be a major risk factor for osteonecrosis of the jaw. The study findings suggest that patients should undergo regular dental examinations to detect pulp and periapical disease before or during the administration of bisphosphonates and that root canal treatment should be considered to decrease the risk of osteonecrosis of the jaw.

• Restorative Dentistry and Endodontics
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• v.37 no.2
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• pp.123-126
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• 2012

It is often presumed that apical periodontitis follows total pulp necrosis, and consequently root canal treatment is commonly performed. Periapical lesion development is usually caused by bacteria and its byproduct which irritate pulp, develop pulpitis, and result in necrosis through an irreversible process. Afterwards, apical periodontitis occurs. This phenomenon is observed as an apical radiolucency in radiographic view. However, this unusual case presents a spontaneous healing of periapical lesion, which has developed without pulp necrosis in a vital tooth, through conservative treatment.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.15-24
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• 1983

Irradiation is frequently employed as the sole therapy for oral cancer. These irradiated patients presents peculiar and progressive dental problems. But there is only scanty informations concerning specific approaches to endodontic treatment for head and neck cancer patients who have been subjected to tumorcidal doses of radiation therapy. The purpose of the present study was to determine the effects of cobalt-60 radiation on the pulpal healing of dogs after the direct pulp capping. As the experimental animals, 10 dogs (above 7-8 months after birth) were divided into 3 groups (Control, Group I, Group II). The cobalt-60 was irradiated to the Group I and Group II each 1,009 and 1,562.5 rads as single dose. As the capping material Dycal$^{(R)}$(L.D. Caulk company) was selected. After the direct pulp capping the dogs were sacrified 1, 2, 3, 4, week interval and made the original slides cut with a thickness of 8 microns and stained with hematoxylin and eosin. After examination and comparision of all specimen, the results of this study were drawn as follows; 1. The formation of reparative dentin was observed from the 1st week in the Control group, the 2nd week in the Group I & II. The few and irregular tuble structure was appeared in the 4th week in the Control group only, but failed in the Group I & II. 2. The continuity of dentin bridge was appeared in the 3rd week in all group and the degeneration of odontoblast in the 1st week of the Group II. 3. The congestion and hemorrhage in the pulp tissue were observed in all groups until 3rd week. The inflammation was appeared within the 2nd week in the Group I and especially marked in the Group II, but absent in the Control group. 4. In cases Dycal into the pulp tissue deeply, the local necrosis of pulp and decrease of dentin formation was observed.

• International Journal of Oral Biology
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• v.37 no.2
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• pp.77-83
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• 2012

We investigated the pulpal response to direct pulp capping in rat molar teeth using mineral trioxide aggregate (MTA) and calcium hydroxide (CH). A palatal cavity was prepared in rat maxillary molar teeth. Either MTA or CH was placed on the exposed pulp and all cavities were restored with composite. Rats were sacrificed for histological evaluation after 12 hours and at 2, 7, 14 and 21 days. In both the MTA and CH groups, reparative dentin formation was clearly observed on histology after 14 days. The MTA-capped pulps were found to be mostly free from inflammation, and hard tissue of a tubular consistent barrier was observed. In contrast, in CH-capped teeth, excessive formation of reparative dentin toward residual pulp was evident. The pulpal cell response beneath the reparative dentin layer was examined by immunofluorescence using antibodies against DSP. After 2 days, a few DSP immunopositive cells, most of which showed a cuboidal shape, appeared beneath the predentin layer. At 7 days, DSP-immunopositive cells with columnar odontoblast-like cells were seen beneath the newly formed hard tissues. At 14 and 21 days, DSP was more abundant in the vicinity of the odontoblastic process along the dentinal tubules than in the mineralized reparative dentin. The CH group showed strong expression patterns in terms of DSP immunoreactivity. Our results thus indicate that MTA may be a more effective pulp capping material as it induces the differentiation of odontoblast-like cells and the formation of reparative dentin without the loss of residual pulp functions.

• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.12.1-12.11
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• 2023

Objectives: The present study evaluated the pulp response of human mandibular incisors subjected to in-office dental bleaching using gels with medium or high concentrations of hydrogen peroxide (HP). Materials and Methods: The following groups were compared: 35% HP (HP35; n = 5) or 20% HP (HP20; n = 4). In the control group (CONT; n = 2), no dental bleaching was performed. The color change (CC) was registered at baseline and after 2 days using the Vita Classical shade guide. Tooth sensitivity (TS) was also recorded for 2 days post-bleaching. The teeth were extracted 2 days after the clinical procedure and subjected to histological analysis. The CC and overall scores for histological evaluation were evaluated by the Kruskal-Wallis and Mann-Whitney tests. The percentage of patients with TS was evaluated by the Fisher exact test (α = 0.05). Results: The CC and TS of the HP35 group were significantly higher than those of the CONT group (p < 0.05) and the HP20 group showed an intermediate response, without significant differences from either the HP35 or CONT group (p > 0.05). In both experimental groups, the coronal pulp tissue exhibited partial necrosis associated with tertiary dentin deposition. Overall, the subjacent pulp tissue exhibited a mild inflammatory response. Conclusions: In-office bleaching therapies using bleaching gels with 20% or 35% HP caused similar pulp damage to the mandibular incisors, characterized by partial necrosis, tertiary dentin deposition, and mild inflammation.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.27-40
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• 1997

This study investigated the effects of laser irradiation on the exposed pulp and the possibility of direct pulp capping with the $CO_2$ laser. Results were obtained from the observation of the residual pulpal healing process. Class V cavities on 48 anterior teeth from 8 adult dogs were prepared and pulp chambers were intentionally opened with dental explorer. The control group consisted of 16 teeth. $Dycal^{(R)}$(Caulk Co., U.S.A.) was applied to exposed site once bleeding was stopped. Cavities were sealed with $I.R.M^{(R)}$. In the experimental group 1 (16 teeth), laser(LASERSAT $CO_2^{(R)}$, Satelec Co.) was irradiated on the exposed pulp. The laser procedure followed the manufacturers recommendations for the treatment of human pulp(1.5 Watts, 0.2 seconds, unfocused), and cavities were sealed with $I.R.M^{(R)}$. In the experimental group 2 (16 teeth), laser was irradiated on the exposed pulp in a more powerful dosage(5.0 Watts, 0.2 seconds, unfocused), and cavities were sealed with $I.R.M^{(R)}$. Two dogs were sacrificed immediately after experiment and the others were sacrificed at intervals of one, three, and eight weeks respectively. All teeth were routinely processed and the pulpal tissues and odontoblastic layers were observed by the light microscope. The results were as follows; 1. In the control group, the initial mild inflammation had improved to normal by week eight. An active formation of reparative dentin was observed at week three, and at week eight, a firm dentin bridge was present beneath the $Dycal^{(R)}$ with no inflammatory responses in the remaining pulp. 2. In the experimental group 1, immediately following irradiation, the superficial shape of the exposed pulp was crater-like. And it was lined with the coagulated layer, $60{\sim}70{\mu}m$ in width. Moderate inflammatory pulpal conditions existing at week one were improved to mild at week eight. And from the week three specimens, a reparative dentin formation was observed in the adjacent odontoblastic layer of the exposed site. A dentin bridge at the exposed site, however, did not form during the experimental period. 3. In the experimental group 2, the width of the coagulation layer lining the crater was $70{\sim}130{\mu}m$. Beneath the coagulated layer, severe inflammatory pulpal responses were observed at week one, and conditions did not improve during the experimental period.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.591-591
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• 2003

Apical periodontitis is inflammation of the periodontium caused by infection of the pulp canal system. Moreover, a dental periradicular lesion occurs as a periradicular tissue reaction to bacterial infection and consists of periradicular inflammation with alveolar bone destruction and root resorption, a consequence of the interaction between oral flora and the existing host defenses. Many investigations dealing with the pathogenesis and history of periradicular lesions have described histologically, immunologically, biochemically the development of the periradicular lesion；but none of these studies have shown any correlation between this lesion and several factors, the whole body disease in the worldwide.(omitted)

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.616-622
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• 1999

The primary objective of pulp treatment is to maintain the integrity and health of the oral tissues. The most important and difficult aspect of pulp therapy is determining the health of the pulp, or its stage of inflammation, so that a decision can be made regarding the best form of treatment. Immature permanent teeth are good candidates for many pulp healing procedures, due to their rich blood supply, which is believed to enhance the pulp's ability to react successfully to various insults. Healing was considered to have taken place when the tooth fulfilled the following criteria: 1. Abscence of clinical symtoms 2. Radiographic evidence of dentin bridge formation 3. No intrapulpal or periapical pathosis was evident radiographically 4. Continued root development and closure of the apex in immature teeth 5. Normal dentin apposition in mature teeth 6. Positive response to electrical pulp test This presents a report of cases in which immature permanent teeth, pulp-exposed by caries or trauma, was treated successfully by partial pulpotomy.