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Tewari N, Rajeswary A, Wikström A, Tsilingaridis G. Non-Surgical Endodontic Management of Large Periapical Lesions After Traumatic Dental Injuries. Dent Traumatol 2025; 41 Suppl 1:43-52. [PMID: 39487669 DOI: 10.1111/edt.13008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2024] [Revised: 10/07/2024] [Accepted: 10/08/2024] [Indexed: 11/04/2024]
Abstract
Traumatic dental injuries of permanent teeth result in multiple immediate and long-term consequences depending upon the severity of trauma, age of the patient, the status of root maturity, and the emergency care provided. The healing responses may get disturbed due to severe damage, loss of vascularity of the supporting structures, and infections. As a result, the prohealing mediators and pathways are overpowered by the destructive stimuli often manifested by an increased osteoclastic activity. Among the various late complications, the apical periodontitis or the periapical lesions are most worrisome for the patients and create clinical dilemma for the dentists. In the past, many such lesions were classified as cysts and subjected to surgical management. However, better understanding of lesion pathophysiology, three-dimensional imaging, and molecular pathways have established their inflammatory nature. The advancements in materials such as calcium silicates, and regenerative techniques have propelled the research related to non-surgical endodontic management as its clinical acceptability. The treatment largely follows the recommendations of regenerative medicine and is based on four principles: (a) establishing the drainage or an endodontic access to the area, (b) removal of most of the triggering agents such as necrosed pulp, toxins, and inflammatory mediators, (c) disinfection of the area, controlling inflammation and reversal of the acidic pH, and (d) maintenance of this infection/inflammation-free state for a long time through adequate sealing. This review aims to highlight the rationale of the approach, case selection, pathophysiology of the causation and healing, clinical protocols, and the limitations of non-surgical endodontic management of large periapical lesions secondary to traumatic dental injuries.
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Affiliation(s)
- Nitesh Tewari
- Division of Pediatric and Preventive Dentistry, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India
| | - Amritha Rajeswary
- Division of Pediatric and Preventive Dentistry, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India
| | - Alina Wikström
- Center of Pediatric Oral Health Research, Stockholm, Sweden
- Department of Endodontics, Public Dental Health Services, Stockholm, Sweden
| | - Georgios Tsilingaridis
- Department of Endodontics, Public Dental Health Services, Stockholm, Sweden
- Division of Paediatric Dentistry, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
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Menon N, Kishen A. Nociceptor-Macrophage Interactions in Apical Periodontitis: How Biomolecules Link Inflammation with Pain. Biomolecules 2023; 13:1193. [PMID: 37627258 PMCID: PMC10452348 DOI: 10.3390/biom13081193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
Periradicular tissues have a rich supply of peripheral afferent neurons, also known as nociceptive neurons, originating from the trigeminal nerve. While their primary function is to relay pain signals to the brain, these are known to be involved in modulating innate and adaptive immunity by initiating neurogenic inflammation (NI). Studies have investigated neuroanatomy and measured the levels of biomolecules such as cytokines and neuropeptides in human saliva, gingival crevicular fluid, or blood/serum samples in apical periodontitis (AP) to validate the possible role of trigeminal nociceptors in inflammation and tissue regeneration. However, the contributions of nociceptors and the mechanisms involved in the neuro-immune interactions in AP are not fully understood. This narrative review addresses the complex biomolecular interactions of trigeminal nociceptors with macrophages, the effector cells of the innate immune system, in the clinical manifestations of AP.
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Affiliation(s)
| | - Anil Kishen
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada;
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Tanzawa S, Kitamura K, Ishikawa N, Tamiya Y, Sako R, Furusawa M, Yamamoto H. Immunohistochemical Observation on the Distribution and Morphological Changes of GAP-43 Positive Structures in the Formation of Experimental Apical Periodontitis of Rat Molars. J HARD TISSUE BIOL 2022. [DOI: 10.2485/jhtb.31.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
| | - Kei Kitamura
- Department of Histology and Developmental Biology, Tokyo Dental College
| | - Noboru Ishikawa
- Department of Forensic Odontology and Anthropology, Tokyo Dental College
| | | | - Ryo Sako
- Department of Endodontics, Tokyo Dental College
| | | | - Hitoshi Yamamoto
- Department of Histology and Developmental Biology, Tokyo Dental College
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Guan X, Zhou Y, Yang Q, Zhu T, Chen X, Deng S, Zhang D. Vital Pulp Therapy in Permanent Teeth with Irreversible Pulpitis Caused by Caries: A Prospective Cohort Study. J Pers Med 2021; 11:jpm11111125. [PMID: 34834477 PMCID: PMC8620894 DOI: 10.3390/jpm11111125] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/19/2021] [Accepted: 10/30/2021] [Indexed: 01/09/2023] Open
Abstract
Background: When a tooth is diagnosed with irreversible pulpitis, root canal therapy (RCT) is generally performed to completely remove pulp tissue, which might lead to a higher risk of loss of vascularity, and teeth being more prone to fracture. Vital pulp therapy (VPT) is a personalized method of treating irreversible pulpitis, which conforms to the trend of minimally invasive endodontics. The remaining vital pulp could promote the physiological development of the roots of young permanent teeth with incomplete apical foramen. However, clear guidelines for VPT indication are still missing. Objective: This prospective cohort study evaluated the outcomes of vital pulp therapy (VPT) using iRoot BP Plus (Innovative Bioceramix Inc, Vancouver, BC, Canada) in permanent teeth of 6- to 20-year-old patients with irreversible pulpitis caused by caries and analyzed the preoperative factors affecting VPT prognosis. Methods: Fifty-nine permanent teeth in 59 patients with irreversible pulpitis caused by caries were treated with VPT using iRoot BP Plus. All patients received VPT under a standardized protocol. After informed consent, teeth were isolated with a dental dam, then operators performed VPT with iRoot BP Plus and restored the teeth with composite resin or stainless steel crown. Patients were postoperatively recalled after 3, 6 and 12 months and then recalled annually. Successful cases were defined as successful in both clinical and radiographic evaluations. A statistical analysis was performed using the Fisher exact test, and the level of significant difference was p < 0.05. Results: After 6–36 months of follow-up, a total of 57 teeth from 57 patients were accessible for evaluation. The mean age of subjects was 11.75 ± 3.81 years. The overall clinical and radiographic success rate of VPT was 91.2% (52/57). With an observation time of one year or more, the success rate was 90.5% (38/42). All the symptoms and physical examination findings showed no significant effect on VPT prognosis (p > 0.05) using a binary logistic regression model. Conclusions: Permanent teeth in 6- to 20-year-old patients diagnosed as irreversible pulpitis caused by caries can be successfully treated with VPT using iRoot BP Plus.
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Ozdogan MS, Gungormus M, Ince Yusufoglu S, Ertem SY, Sonmez C, Orhan M. Salivary opiorphin in dental pain: A potential biomarker for dental disease. Arch Oral Biol 2019; 99:15-21. [DOI: 10.1016/j.archoralbio.2018.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/30/2018] [Accepted: 12/13/2018] [Indexed: 01/20/2023]
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Uesrichai N, Nirunsittirat A, Chuveera P, Srisuwan T, Sastraruji T, Chompu-Inwai P. Partial pulpotomy with two bioactive cements in permanent teeth of 6- to 18-year-old patients with signs and symptoms indicative of irreversible pulpitis: a noninferiority randomized controlled trial. Int Endod J 2019; 52:749-759. [PMID: 30638262 DOI: 10.1111/iej.13071] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/01/2019] [Indexed: 12/20/2022]
Abstract
AIM To compare the outcome of partial pulpotomy using two cements, ProRoot MTA (Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) and Biodentine (Septodont, Saint-Maur-des-Fossés, France), in permanent teeth of 6- to 18-year-old patients with signs and symptoms indicative of irreversible pulpitis. Furthermore, the frequencies of perceptible grey discoloration caused by the cements were compared. METHODOLOGY Sixty-nine permanent first molars with signs and symptoms indicative of irreversible pulpitis, from 69 patients, were included. All operators performed partial pulpotomy under a standardized protocol. Teeth were allocated, using a website-generated number of simple randomization, to partial pulpotomy with either ProRoot MTA (37 teeth) or Biodentine (32 teeth) and were restored with composite resin or stainless steel crowns. Patients were recalled every 6 months. To be categorized as having success, the evaluated tooth must have had both clinical and radiographic success. In addition, photographs of treated teeth were evaluated for frequency of perceptible grey discoloration. Success rates between the two cements were compared using the Fisher exact test. The frequencies of perceptible grey discoloration were compared using the chi-square test. The percentage difference was estimated by 95% confidence interval, and the level of significant difference was P < 0.05. RESULTS At a mean follow-up of 32.2 ± 17.9 months, a total of 67 teeth, 37 with ProRoot MTA and 30 with Biodentine, were available for evaluation. The mean age of participants was 10 ± 2.1 years and, there were no differences in the baseline variables (gender, age, tooth type, periapical status, stage of root development, final restoration and follow-up period) between the groups. The overall success in both groups was 90%, with 92% for ProRoot MTA and 87% for Biodentine (difference, 5%; 95% confidence interval, -9% to 19%, P = 0.487), suggesting that Biodentine was noninferior to ProRoot MTA. Perceptible grey discoloration was observed in both groups, 80% for teeth treated with ProRoot MTA and 27% for teeth treated with Biodentine, with a significant difference between the materials (P < 0.001). CONCLUSIONS Permanent teeth with signs and symptoms indicative of irreversible pulpitis in 6- to 18-year-old patients were successfully treated with partial pulpotomy using both cements. Biodentine exhibited significantly less frequency of discoloration than did ProRoot MTA.
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Affiliation(s)
- N Uesrichai
- Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - A Nirunsittirat
- Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - P Chuveera
- Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - T Srisuwan
- Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - T Sastraruji
- Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - P Chompu-Inwai
- Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
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Andreasen FM, Kahler B. Pulpal Response after Acute Dental Injury in the Permanent Dentition: Clinical Implications—A Review. J Endod 2015; 41:299-308. [DOI: 10.1016/j.joen.2014.11.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/09/2014] [Accepted: 11/27/2014] [Indexed: 12/28/2022]
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Sudhakar V, Vinodhini TS, Mohan AM, Srinivasan B, Rajkumar BK. The efficacy of different pre- and post-operative analgesics in the management of pain after orthodontic separator placement: A randomized clinical trial. J Pharm Bioallied Sci 2014; 6:S80-4. [PMID: 25210391 PMCID: PMC4157287 DOI: 10.4103/0975-7406.137393] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 03/30/2014] [Accepted: 04/09/2014] [Indexed: 11/25/2022] Open
Abstract
Introduction: Pain-free treatment to the patients is considered as an important treatment objective for orthodontic health care providers. However, many orthodontists underestimate the degree of pain experienced by the patients. Hence, this study was conducted as a randomized, double-blinded clinical trial with the following objectives. Objective: To study the pain characteristics after separator placement; to compare the efficacy of various commonly used analgesics in pain management and to determine the efficacy of pre- and post-operative analgesics in pain management. Subjects and Methods: Data were collected from 154 patients (77 males and 77 females, age group of 14-21 years, with mean age of 18.8 years) who reported to Department of Orthodontics. Patients were randomly divided in to four groups. Group 1: Paracetamol 650 mg, Group 2: Ibuprofen 400 mg, Group 3: Aspirin 300 mg, Group 4: Placebo and the study were conducted as a randomized, double-blinded clinical trial. The patients were instructed to take two tablets, one tablet 1 h before separator placement, and the other one after 6 h. The pain evaluations were made by the patients, when teeth not touching (TNT), biting back teeth together, chewing food (CF) using a 100-mm visual analogue scale for 7 days after separator placement. Patients were advised to record the severity of pain. Results: Group 3 (Aspirin 300 mg) showed lowest pain values, followed by Group 2 (ibuprofen 400 mg), and Group 1 (paracetamol 650 mg). All NSAID's achieved good pain control compared to Group 4 (placebo), where the intensity pain was maximum. Conclusion: Pre- and post-operative analgesics were found to be more effective in controlling orthodontic pain, after separator placement at all-time intervals.
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Affiliation(s)
- V Sudhakar
- Department of Orthodontics and Dentofacial Orthopedics, Sathyabama University Dental College and Hospital, Chennai, Tamil Nadu, India
| | - T S Vinodhini
- Department of Oral Medicine and Radiology, Karpaga Vinayaga Institute of Dental Sciences, Chennai, Tamil Nadu, India
| | - A Mathan Mohan
- Department of Oral and Maxillofacial Surgery, Karpaga Vinayaga Institute of Dental Sciences, Chennai, Tamil Nadu, India
| | - B Srinivasan
- Department of Orthodontics, Karpaga Vinayaga Institute of Dental Sciences, Chennai, Tamil Nadu, India
| | - B K Rajkumar
- Department of Orthodontics, Vivekananda Dental College, Tiruchengode, Namakkal, Tamil Nadu, India
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Kramer PR, Woodmansey KF, White R, Primus CM, Opperman LA. Capping a pulpotomy with calcium aluminosilicate cement: comparison to mineral trioxide aggregates. J Endod 2014; 40:1429-34. [PMID: 25146026 DOI: 10.1016/j.joen.2014.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/06/2014] [Accepted: 02/02/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Calcium aluminate cements have shown little affinity for bacterial growth, low toxicity, and immunogenicity when used as a restoration material, but calcium aluminate cements have not been tested in vivo in pulpotomy procedures. METHODS To address this question, a calcium aluminosilicate cement (Quick-Set) was tested along with 2 mineral trioxide aggregates, ProRoot MTA and MTA Plus. These cements were used as a capping agent after pulpotomy. Control rats had no pulpotomy, or the pulpotomy was not capped. Proinflammatory cytokines interleukin (IL)-1β and IL-1α were measured, and histology was performed at 30 and 60 days after capping. The nociceptive response was determined by measuring the lengthening of the rat's meal duration. RESULTS and CONCLUSIONS IL-1β and IL-1α concentrations were reduced in the capped teeth, but no differences were observed among the 3 cements. Dentinal bridging could be detected at both 30 and 60 days with each of the 3 cements, and the pulps were still vital 60 days after capping. Meal duration significantly shortened after placement of the 3 different cements, indicating a nociceptive response, but there were no differences among the materials. Calcium aluminosilicate cement had similar properties to mineral trioxide aggregates and is a viable option for pulpotomy procedures.
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Affiliation(s)
- Phillip R Kramer
- Department of Biomedical Sciences, Texas A and M Baylor College of Dentistry, Dallas, Texas.
| | - Karl F Woodmansey
- Department of Endodontics, Department of Biomedical Sciences, Texas A and M Baylor College of Dentistry, Dallas, Texas
| | - Robert White
- Department of Endodontics, Department of Biomedical Sciences, Texas A and M Baylor College of Dentistry, Dallas, Texas
| | | | - Lynne A Opperman
- Department of Biomedical Sciences, Texas A and M Baylor College of Dentistry, Dallas, Texas
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Tanaka T, Ozeki N, Kawai R, Imaizumi I, Nakata K, Nakamura H. Expression and regulation of a disintegrin and metalloproteinase-8 and -17 in development of rat periradicular lesion. J Endod 2013; 39:638-42. [PMID: 23611382 DOI: 10.1016/j.joen.2012.12.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 12/06/2012] [Accepted: 12/10/2012] [Indexed: 11/18/2022]
Abstract
INTRODUCTION A disintegrin and metalloproteinases (ADAMs) are a family of transmembrane proteins that share a common domain structure. However, little is known about the possible involvement of ADAM-8 and ADAM-17 in the development of periradicular lesions. Here we demonstrated the expression of ADAM-8 and ADAM-17 in rat periradicular lesions. METHODS We induced experimentally periradicular lesions in rats. The animals were killed at 0, 2, 4, 6, and 8 weeks after pulp exposure. The left molars underwent immunofluorescence analysis for both ADAMs and for neutrophil elastase, and right molars were used for reverse transcription-polymerase chain reaction analysis of ADAM-8 and ADAM-17. The areas of these lesions were measured histometrically, and the numbers of all antigen-positive cells in the periapical portion were counted per unit area. RESULTS The area of the periradicular lesions gradually expanded from 0 to 4 weeks, showing a large increase from week 2 to week 4. Both ADAM-8-positive and ADAM-17-positive cells gradually increased in number from 0 to 4 weeks and then decreased from 4 to 8 weeks. There were more ADAM-17-expressing cells than ADAM-8-expressing ones at all experimental periods except at 4 weeks. The highest expression of ADAM-8 mRNA was observed at 4 weeks, and there were significant differences between 0 and 2 weeks and between 4 and 6 weeks. The expression of ADAM-17 mRNA increased from 0 to 4 weeks and subsequently decreased from 4 to 8 weeks, with a significant difference between 4 and 6 weeks. CONCLUSIONS Our results suggest that ADAM-8 and ADAM-17 may be related to the development of rat periradicular lesions.
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Affiliation(s)
- Tsuyoshi Tanaka
- Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.
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Kramer PR, He J, Puri J, Bellinger LL. A non-invasive model for measuring nociception after tooth pulp exposure. J Dent Res 2012; 91:883-7. [PMID: 22797321 DOI: 10.1177/0022034512454297] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Temporomandibular arthritis will lengthen a rodent's meal duration. We hypothesized that meal duration would also lengthen after tooth pulp exposure, suggesting that this behavior could be used to measure tooth nociception. To test this hypothesis, we placed rats in feeding units and subjected 4 anterior mandibular molars to pulp exposure, with and without pre-treatment with the analgesic buprenorphine-HCl. In the first study, male Sprague-Dawley rats were placed in computerized sound-attenuated feeding modules, the pulp of 4 molars on the mandible were exposed, and meal duration was measured for 13 days. In a second study, rats were injected with either the analgesic buprenorphine-HCl or saline every 12 hrs; injections were started one day before pulp exposure. Meal duration was determined before and after treatment. In the first study, pulp exposure significantly increased daily meal duration for 8 days. In the second study, pulp exposure lengthened daily meal duration, but the group that was treated with buprenorphine-HCl showed no significant difference compared with control rats without pulp exposure. Evidence supports that a lengthening in meal duration is a response to tooth nociception and that this nociception can be measured for over a week.
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Affiliation(s)
- P R Kramer
- Department of Biomedical Sciences, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX 75246, USA
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Kim HJ, Lee SJ, Jung IY, Park SH. Vital tooth with periapical lesion: spontaneous healing after conservative treatment. Restor Dent Endod 2012. [DOI: 10.5395/rde.2012.37.2.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Hyun-Joo Kim
- Department of Conservative Dentistry, Yonsei University College of Dentistry, Seoul, Korea
| | - Seung-Jong Lee
- Department of Conservative Dentistry, Yonsei University College of Dentistry, Seoul, Korea
| | - Il-Young Jung
- Department of Conservative Dentistry, Yonsei University College of Dentistry, Seoul, Korea
| | - Sung-Ho Park
- Department of Conservative Dentistry, Yonsei University College of Dentistry, Seoul, Korea
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Chen MYH, Chen KL, Chen CA, Tayebaty F, Rosenberg PA, Lin LM. Responses of immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures. Int Endod J 2011; 45:294-305. [DOI: 10.1111/j.1365-2591.2011.01978.x] [Citation(s) in RCA: 226] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
Pain is one of the most common reasons for which patients seek dental and medical care. Orofacial pain conditions consist of a wide range of disorders including odontalgia (toothache), temporomandibular disorders, trigeminal neuralgia and others. Most of these conditions are either inflammatory or neuropathic in nature. This chapter provides an overview of the commonly used models to study inflammatory and neuropathic orofacial pain.
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Affiliation(s)
- Asma Khan
- Department of Endodontics, University of North Carolina, Chapel Hill, NC, USA
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Dammaschke T. Rat molar teeth as a study model for direct pulp capping research in dentistry. Lab Anim 2010; 44:1-6. [DOI: 10.1258/la.2009.008120] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of this review is to evaluate the suitability of rat molar teeth in preclinical evaluation of medical devices for direct pulp capping. The ISO standard 7405 states clearly that only non-rodent mammals are suitable species for animal research in dentistry. Furthermore, without clear justification a considerable number of researchers previously rejected results of animal experiments concerning preclinical evaluation of the biocompatibility of dental materials undertaken in rat molar teeth. However, in the past 50 years about 70 studies have been published using rat molar teeth in order to evaluate direct pulp capping, pulpotomies and tissue reactions after pulp exposure. Numerous studies showed that the healing of rat molar pulp tissue after direct pulp capping is histologically comparable with humans and other animal species pulp tissue. Rat molar teeth, including pulp tissue, can be seen anatomically, histologically, biologically, and physiologically as miniature human molar teeth. Hence, the essential biological reactions of the pulp tissue and the interaction during the different stages of wound healing of rat molar teeth are comparable with that of other mammals. Rat molar teeth are a valid study model in order to provide valuable data concerning pulp tissue reaction after direct pulp capping and related questions in dentistry. Therefore, the use of rats may significantly reduce the number of currently used higher animals in research. Tests in higher developed animals should be limited to experiments which clarify inconsistent results. However, some technical difficulties, like the small size of rat molar teeth must be dealt with before undertaking any research.
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Affiliation(s)
- Till Dammaschke
- Westphalian Wilhelms University, Department of Operative Dentistry, Waldeyerstr. 30, 48149 Münster, Germany
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Bletsa A, Fristad I, Berggreen E. Sensory pulpal nerve fibres and trigeminal ganglion neurons express IL-1RI: a potential mechanism for development of inflammatory hyperalgesia. Int Endod J 2009; 42:978-86. [PMID: 19732182 DOI: 10.1111/j.1365-2591.2009.01605.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To localize interleukin-1 receptor type I (IL-1RI) in rat dental pulp and trigeminal ganglion (TG) and to test the hypothesis that pulpal inflammation increases neuronal expression of IL-1RI. METHODOLOGY Female Wistar rats were subjected to unilateral pulp exposures in the maxillary and mandibular first molars, whereas the contralateral jaws served as untreated controls. Seven days later the animals were transcardiacally perfused and the jaws and the TGs were removed and prepared for immunohistochemistry. Immunoreactivity for IL-1RI was examined alone (DAB) and together with calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), CD31 or CD34 by multiple-labelling immunofluorescence. Quantification of IL-1RI-immunoreactive (-IR) cells in the maxillary and mandibular division of the ganglion was performed in parasagittal immunoreacted sections of the right and left TGs. Data were analysed with Mann-Whitney Rank Sum test (P < 0.05). RESULTS Interleukin-1 receptor type I was found on sensory (CGRP-IR) and sympathetic (NPY-IR) nerve fibres and on blood vessels (CD31- and CD34-IR) in the dental pulp. It was also localized on sensory neurons and axons in the TG. Pulpal inflammation significantly increased the expression of IL-1RI in the TG (P < 0.001). CONCLUSIONS The localization of IL-1RI on sensory nerve fibres and its up-regulation in TG neurons during pulpal inflammation may imply a direct effect of IL-1 in pulpal nociception. The presence of IL-1RI on sympathetic nerve fibres and on blood vessels may indicate a vasoactive role of the same cytokine in the pulp.
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Affiliation(s)
- A Bletsa
- Department of Biomedicine, Faculty of Medicine and Dentistry, Univeristy of Bergen, Bergen, Norway.
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Khan AA, Sun X, Hargreaves KM. Effect of calcium hydroxide on proinflammatory cytokines and neuropeptides. J Endod 2008; 34:1360-1363. [PMID: 18928847 DOI: 10.1016/j.joen.2008.08.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 08/06/2008] [Accepted: 08/11/2008] [Indexed: 11/28/2022]
Abstract
Calcium hydroxide, a widely used intracanal medicament, is known to exert an antimicrobial effect and to degrade bacterial-derived lipopolysaccharides. However, little is known about the effect of Ca(OH)(2) on endogenous inflammatory mediators such as interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), and calcitonin gene-related peptide (CGRP). This is an important gap in knowledge because these inflammatory mediators play an important role in mediating the pathogenesis of periradicular periodontitis. We tested the hypothesis that Ca(OH)(2) denatures IL-1 alpha, TNF-alpha, and CGRP. Human IL-1 alpha (0.125 ng/mL), TNF-alpha (0.2 ng/mL), and CGRP (0.25 ng/mL) were incubated with Ca(OH)(2) (0.035 mg/mL) for 1-7 days. At the end of the incubation period, the pH of the samples was neutralized, and the concentrations of the mediators were measured by immunoassays. Data were analyzed with one-way analysis of variance and Bonferroni multiple comparison tests. The results indicate that Ca(OH)(2) denatures IL-1 alpha, TNF-alpha, and CGRP by 50%-100% during the testing periods (P < .001). We concluded that denaturation of these proinflammatory mediators is a potential mechanism by which Ca(OH)(2) contributes to the resolution of periradicular periodontitis.
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Affiliation(s)
- Asma A Khan
- Department of Endodontics, University of North Carolina, Chapel Hill, North Carolina.
| | - Xiaoling Sun
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Kenneth M Hargreaves
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX
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FRISTAD INGE, BLETSA ATHANASIA, BYERS MARGARET. Inflammatory nerve responses in the dental pulp. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1601-1546.2010.00247.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Souza PPC, Fukada SY, Cunha FQ, Costa CAS, Costa-Neto CM. Regulation of angiotensin II receptors levels during rat induced pulpitis. ACTA ACUST UNITED AC 2007; 140:27-31. [PMID: 17197045 DOI: 10.1016/j.regpep.2006.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 06/06/2006] [Accepted: 11/10/2006] [Indexed: 11/18/2022]
Abstract
A change in the microcirculatory hemodynamic is one of the most important events in inflammation. In the dental pulp, which is a connective tissue surrounded by a mineralized dentine substrate, disturbance in the blood flow as well as plasma extravasation may increase the pulp pressure and cause local ischemia. The octapeptide angiotensin II (AngII) regulates vascular tone and stimulates the release of pro-inflammatory cytokines by acting through the AT1 and AT2 receptors. The AT1 receptor is responsible for the classical effects of AngII. The AT2 receptor is involved in other effects, such as vasodilation. Therefore, we aimed to evaluate the role of AT1 and AT2 receptors on the pulpal inflammation. The pulp tissue was mechanically exposed and after different periods the teeth were extracted and submitted to histopathological and RT-PCR analyses. The histological sections showed a number of congested and dilated blood vessels associated with a notable presence of inflammatory cells. RT-PCR data revealed that the AT1 receptor was down-regulated at 24 h after the pulp exposure. The AT2 receptor expression was up-regulated by a 9-hour period, and then decreased between 12- and 24-hour periods. It was demonstrated that the renin-angiotensin system plays an important role in the pulpal inflammation, with regulation of AngII receptor levels.
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Affiliation(s)
- Pedro P C Souza
- Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, Brazil
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20
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Worsley MA, Davies SL, Clayton NM, Bountra C, Loescher AR, Robinson PP, Boissonade FM. The effect of inflammation on Fos expression in the ferret trigeminal nucleus. Eur J Oral Sci 2007; 115:40-7. [PMID: 17305715 DOI: 10.1111/j.1600-0722.2007.00411.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We have previously carried out detailed characterization and identification of Fos expression within the trigeminal nucleus after tooth pulp stimulation in ferrets. The aim of this study was to determine the effect of pulpal inflammation on the excitability of central trigeminal neurons following tooth pulp stimulation. Adult ferrets were prepared under anesthesia to allow tooth pulp stimulation, recording from the digastric muscle, and intravenous injections at a subsequent experiment. In some animals, pulpal inflammation was induced by introducing human caries into a deep buccal cavity. After 5 d, animals were re-anaethetized, and the teeth were stimulated at 10 times the threshold of the jaw-opening reflex. Stimulation of all tooth pulps induced ipsilateral Fos in the trigeminal subnuclei caudalis and oralis. All non-stimulated animals showed negligible Fos labeling, with no differences recorded between inflamed and non-inflamed groups. Following tooth pulp stimulation, Fos expression was greater in animals with inflamed teeth than in animals with non-inflamed teeth, with the greatest effect seen in the subnucleus caudalis. These results suggest that inflammation increases the number of trigeminal brainstem neurons activated by tooth pulp stimulation; this may be mediated by peripheral or central mechanisms.
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Affiliation(s)
- Matthew A Worsley
- Department of Oral and Maxillofacial Medicine and Surgery, School of Clinical Dentistry, University of Sheffield, UK.
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21
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Yang H, Bernanke JM, Naftel JP. Immunocytochemical evidence that most sensory neurons of the rat molar pulp express receptors for both glial cell line-derived neurotrophic factor and nerve growth factor. Arch Oral Biol 2006; 51:69-78. [PMID: 16444814 DOI: 10.1016/j.archoralbio.2005.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Most pulpal afferent neurons have cytochemical features in common with the class of nociceptors that express neuropeptides and respond to NGF, while very few bind the plant lectin IB4, a widely used marker for the class of nociceptors that respond to the GDNF family of neurotrophic factors. The present study was undertaken to determine whether the GDNF receptor, GFRalpha-1, is expressed by pulpal afferents, and, further, to determine whether tooth injury evokes changes in expression of the GDNF and NGF receptors among pulpal afferents. The tracer, fluoro-gold (FG), was applied to shallow cavities in dentin of first and second maxillary molars. After 4 weeks, the molars of one side received a test injury consisting of a deeper cavity that exposed pulp horns. Animals were perfusion fixed 2 days later, and sections of the trigeminal ganglia were double immunostained with combinations of antibodies against GFRalpha-1, and TrkA. Under control conditions, GFRalpha-1 immunostaining was observed in 72% of neurons that projected to the molar pulp, TrkA in 78%, and immunostaining for both receptors was observed in 65% of pulpal afferents. Tooth injury evoked up-regulation of GFRalpha-1 expression (to 93%) and a slight down-regulation of TrkA expression (67%) among tooth afferents, while there was no discernable change in the proportion of pulpal afferents that expressed both TrkA and GFRalpha-1 (to 61%).
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Affiliation(s)
- Hong Yang
- Department of Anatomy, University of Mississippi Medical Center, Jackson, 39216, USA
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22
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SAITO I, OKAMOTO Y, GOGEN H, SHANFELD J, HANADA K, DAVIDOVITCH Z. Alterations in staining intensity for calcitonin gene-related peptide (CGRP) in osteoblasts of the periodontal ligament during orthodontic tooth movement. Biomed Res 2004. [DOI: 10.2220/biomedres.25.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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23
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Byers MR, Suzuki H, Maeda T. Dental neuroplasticity, neuro-pulpal interactions, and nerve regeneration. Microsc Res Tech 2003; 60:503-15. [PMID: 12619126 DOI: 10.1002/jemt.10291] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review covers current information about the ability of dental nerves to regenerate and the role of tooth pulp in recruitment of regenerating nerve fibers. In addition, the participation of dental nerves in pulpal injury responses and healing is discussed, especially concerning pulp regeneration and reinnervation after tooth replantation. The complex innervation of teeth is highly asymmetric and guided towards specific microenvironments along blood vessels or in the crown pulp and dentin. Pulpal products such as nerve growth factor are distributed in the same asymmetric gradients as the dentinal sensory innervation, suggesting regulation and recruitment of those nerve fibers by those specific factors. The nerve fibers have important effects on pulpal blood flow and inflammation, while their sprouting and cytochemical changes after tooth injury are in response to altered pulpal cytochemistry. Thus, their pattern and neuropeptide intensity are indicators of pulp status, while their local actions continually affect that status. When denervated teeth are injured, either by pulp exposure on the occlusal surface or by replantation, they have more pulpal necrosis than occurs for innervated teeth. However, small pulp exposures on the side of denervated crowns or larger lesions in germ-free animals can heal well, showing the value of postoperative protection from occlusal trauma or from infection. Current ideas about dental neuroplasticity, neuro-pulpal interactions, and nerve regeneration are related to the overall topics of tooth biomimetics and pulp/dentin regeneration.
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Affiliation(s)
- Margaret R Byers
- Department of Anesthesiology, University of Washington, Seattle 98195-6540, USA.
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24
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Zhang M, Fukuyama H, Zhang JQ, Tanaka T. Immunoelectron Microscopic Study of CGRP-Immunoreactive Nerve Terminals in Wound Healing and Dentin Bridge Formation after Pulpotomy in Rat Molar. Acta Histochem Cytochem 2003. [DOI: 10.1267/ahc.36.43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Min Zhang
- Department of Oral Pathology, Kyushu Dental College
| | | | - Jing-Qi Zhang
- Department of Oral Anatomy and Cell Biology, Graduate School of Dental Sciences, Kyushu University
| | - Teruo Tanaka
- Department of Oral Anatomy and Cell Biology, Graduate School of Dental Sciences, Kyushu University
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25
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Chattipakorn SC, Sigurdsson A, Light AR, Narhi M, Maixner W. Trigeminal c-Fos expression and behavioral responses to pulpal inflammation in ferrets. Pain 2002; 99:61-9. [PMID: 12237184 DOI: 10.1016/s0304-3959(02)00054-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Injury to peripheral dental tissues evokes dynamic alternations in central sensory pathways. We have previously reported that transient stimulation of the dental pulp with noxious heat evokes the induction of the immediate early gene product Fos in the transitional region between subnucleus interpolaris and caudalis (Vi/Vc) and subnucleus caudalis (Vc). A question arises as to whether similar changes occur in response to inflammation to the tooth pulp. In this study, the effects of pulpal inflammation produced by bacterial lipopolysaccharide (LPS) on face-grooming behavior and trigeminal Fos expression were examined. Face-grooming behaviors were recorded daily for 3 days pre- and 24, 48 and 72 h post- LPS or saline application. All animals were perfused 72 h post- LPS or saline application. Brainstems were processed for Fos-like immunoreactivity (Fos-LI). Teeth were processed for H&E staining. Histological examination of LPS-treated teeth revealed features of an acute pulpitis. Moreover, LPS-treated animals showed greater face-grooming activity (i.e. tongue protrusions) directed to the injured tooth than the sham-operated group. The number of Fos-positive neurons was greater in the trigeminal subnucleus caudalis (Vc) and the transitional regions (Vi/Vc) in LPS-treated animals compared with sham-operated animals, and greater in the deeper laminae than the superficial laminae of each trigeminal region. LPS treatment did not evoke Fos expression in the rostral trigeminal regions above Vi/Vc. These results demonstrate that LPS-induced pulpal inflammation results in significant alterations in the Vi/Vc and Vc, and such changes may underlie the observed nociceptive behavioral responses and may play an important role in producing a symptomatic pulpitis in humans.
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26
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Rodd HD, Boissonade FM. Comparative immunohistochemical analysis of the peptidergic innervation of human primary and permanent tooth pulp. Arch Oral Biol 2002; 47:375-85. [PMID: 12015218 DOI: 10.1016/s0003-9969(02)00012-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This immunohistochemical study sought to determine whether there are any differences in the peptidergic innervation of these pulps and whether dental caries is associated with changes in neuropeptide expression. Mandibular first permanent molars and second primary molars (n=120) were obtained from children requiring dental extractions under general anaesthesia. Extracted teeth were split longitudinally, placed in fixative, and categorized as intact, moderately carious or grossly carious. The coronal pulps were removed and 10-microm frozen sections were processed for indirect immunofluorescence. Double labelling employed combinations of the following antisera: (1) protein gene product 9.5, a general neuronal marker; (2) one of the neuropeptides calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), galanin (GAL), enkephalin (ENK) and somatostatin (SOM). Image analysis was then used to determine the percentage area of immunostaining for each label within different anatomical regions of the coronal pulp. Sparse or absent immunoreactivity for GAL, ENK and SOM made analysis impossible. Analysis of CGRP, SP and VIP revealed significant interdentition differences, with their expression being significantly greater in permanent teeth, but this was not the case for NPY, with primary and permanent teeth demonstrating a similar amount of label for this peptide. Both dentitions showed significant increases in CGRP, SP, VIP and NPY expression with caries progression. These findings could have biological and clinical importance in connection with nociception, inflammation and healing.
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Affiliation(s)
- Helen D Rodd
- School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK.
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27
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Abstract
AIM To report the healing of a large periapical lesion following non-surgical root canal treatment. SUMMARY A 12-year-old male with a large periapical lesion around the apices of his mandibular incisors is described. The lesion formed after trauma to the mandibular anterior teeth 5 years previously. During root canal treatment, chlorhexidine gluconate was used for irrigation, and calcium hydroxide was used both for the intracanal dressing and as a base of the root canal sealer. Periapical healing was observed 3 months after obturation and continued at the 12-month review. Key learning points Root canal treatment, including the use of chlorhexidine gluconate and calcium hydroxide for infection control, led to substantial healing of a large periapical lesion. This report confirms that large periapical lesions can respond favourably to non-surgical treatment.
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Affiliation(s)
- M D Oztan
- Department of Endodontics, Faculty of Dentistry, Ankara University, Turkey.
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28
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Affiliation(s)
- J E Bouquot
- The Maxillofacial Center for Diagnostics & Research, Morgantown, WV, USA.
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29
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Byers MR, Chudler EH, Iadarola MJ. Chronic tooth pulp inflammation causes transient and persistent expression of Fos in dynorphin-rich regions of rat brainstem. Brain Res 2000; 861:191-207. [PMID: 10760482 DOI: 10.1016/s0006-8993(00)01936-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have analyzed central Fos immunoreactivity (Fos-IR) brainstems of adult rats after three clinically relevant dental injuries: filled dentin (DF) cavities that cause mild pulp injury and heal within 1-2 weeks; open pulp exposures (PX) that cause gradual pulp loss and subsequent periodontal lesions; and filled pulp exposures (PXF). By 1 week after DF cavities, no Fos-IR remained except for sites such as lateral-ventral periolivary nucleus (LVPO) that had Fos-IR in all rats including controls. PX injury induced (1) a delayed transient expression of Fos at 1-2 weeks at three loci (ipsilateral neurons in dorsomedial nucleus oralis, paratrigeminal nucleus, and trigeminal tract), (2) persistent ipsilateral Fos for at least 4 weeks after injury in dynorphin (Dyn)-rich regions (rostral lateral solitary nucleus, periobex dorsal nucleus caudalis), and (3) late Fos-IR at 2-4 weeks (bilateral superficial cervical dorsal horn, contralateral dorsal nucleus caudalis, contralateral rostral lateral solitary nucleus). Rats with PXF injury were examined at 2 weeks, and they had greater numbers and more extensive rostro-caudal distribution of Fos neurons than the PX group. One week after PX injury, Fos-IR neurons were found in regions with strong Dyn-IR central fibers. Co-expression of Dyn and Fos was found in some unusually large neurons of the ipsilateral rostral lateral solitary nucleus, trigeminal tract, and dorsal nucleus caudalis. Immunocytochemistry for the p75 low affinity neurotrophin receptor (p75NTR) or for calcitonin gene-related peptide (CGRP) showed no consistent change in trigeminal central endings in any Fos-reactive brainstem areas, despite the extensive structural and cytochemical reorganization of the peripheral endings of the dental neurons. The Fos responses of central neurons to tooth injury have some unusual temporal and spatial patterns in adult rats compared to other trigeminal injury models.
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Affiliation(s)
- M R Byers
- Department of Anesthesiology, University of Washington, Seattle, WA 98195-6540, USA.
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30
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Law AS, Baumgardner KR, Meller ST, Gebhart GF. Localization and changes in NADPH-diaphorase reactivity and nitric oxide synthase immunoreactivity in rat pulp following tooth preparation. J Dent Res 1999; 78:1585-95. [PMID: 10520963 DOI: 10.1177/00220345990780100301] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Inflammatory changes in the dental pulp are accompanied by release of a wide variety of chemical mediators. Nitric oxide, an oxidative free radical produced by the enzyme nitric oxide synthase (NOS), has been implicated in multiple inflammatory processes, which makes it a suitable marker for changes which likely occur following tooth pulp insult. Since limited information on nitric oxide in the pulp is available, it is necessary first to examine relative distributions of NOS in uninflamed and inflamed rat pulp. We accomplished this by characterizing regions of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity and the distribution of both macrophage NOS (macNOS) and neuronal NOS (nNOS) immunoreactivity in normal and inflamed rat molar pulp at multiple time points. The results showed that: (1) deep cavity preparation on the mesial surface of the molar produced a time-dependent inflammation, with acute inflammation early progressing to chronic, granulomatous inflammation with necrosis later that spread preferentially down the mesial root; (2) control (non-prepared) teeth showed a relatively faint and homogeneous distribution of NADPH-d and macNOS reactivity but no discernible nNOS reactivity; (3) inflamed teeth displayed localized increased intensity of NADPH-d and macNOS reactivity surrounding the inflamed area of pulp, but no increased nNOS activity; (4) pulp vessels supplying the inflamed area showed increased NADPH-d reactivity, but no increased macNOS or nNOS reactivity; and (5) neither NADPH-d, macNOS, nor nNOS reactivity was observed in pulpal nerves. Therefore, nitric oxide may mediate the pulpal inflammatory response through its effects on the paralesional pulp tissue and surrounding endothelial/vascular structures.
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Affiliation(s)
- A S Law
- Department of Endodontics, University of Iowa, Iowa City, USA
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31
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Tidwell E, Witherspoon DE, Gutmann JL, Vreeland DL, Sweet PM. Thermal sensitivity of endodontically treated teeth. Int Endod J 1999; 32:138-45. [PMID: 10371910 DOI: 10.1046/j.1365-2591.1999.00197.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE REPORTS The problem of thermal sensitivity following non-surgical root-canal treatment is explored and case reports are presented. Possible causes for post-treatment discomfort from endodontic and restorative aetiologies are discussed, as are the mechanisms to explain the patients' painful experiences. Treatment of this problem may vary from the simple replacement of a defective restoration to a more extensive non-surgical retreatment of the case, despite radiographic evidence of an acceptable root filling and normal periradicular tissues.
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Affiliation(s)
- E Tidwell
- Department of Restorative Sciences, Texas A & M University Baylor College of Dentistry, Dallas 75246, USA
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32
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Stashenko P, Teles R, D'Souza R. Periapical inflammatory responses and their modulation. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1998; 9:498-521. [PMID: 9825224 DOI: 10.1177/10454411980090040701] [Citation(s) in RCA: 263] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Periapical inflammatory responses occur as a consequence of bacterial infection of the dental pulp, as a result of caries, trauma, or iatrogenic insult. Periapical inflammation stimulates the formation of granulomas and cysts, with the destruction of bone. These inflammatory responses are complex and consist of diverse elements. Immediate-type responses--including vasodilatation, increased vascular permeability, and leukocyte extravasation--are mediated by endogenous mediators, including prostanoids, kinins, and neuropeptides. Non-specific immune responses--including polymorphonuclear leukocyte and monocyte migration and activation, and cytokine production--are elicited in response to bacteria and their products. Interleukin-1 and prostaglandins in particular have been implicated as central mediators of periapical bone resorption. Chronic periapical inflammation further involves specific T- and B-cell-mediated anti-bacterial responses, and activates a network of regulatory cytokines which are produced by Th1- and Th2-type T-lymphocytes. Various naturally occurring and genetically engineered models of immunodeficiency are beginning to help elucidate those components of the immune system which protect the pulpal/periapical complex. Both specific and non-specific responses interface with and are regulated by the neural system. The modulation of these responses by immune response modifies, cytokine antagonists, and other novel therapeutic agents is discussed. As an experimental model, periapical inflammation has many advantages which permit it to be used in studies of microbial ecology and pathogenesis, host response, neuroimmunology, and bone resorption and regeneration.
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Affiliation(s)
- P Stashenko
- Department of Cytokine Biology, Forsyth Dental Center, Boston, Massachusetts, USA
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33
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Nørholt SE. Treatment of acute pain following removal of mandibular third molars. Use of the dental pain model in pharmacological research and development of a comparable animal model. Int J Oral Maxillofac Surg 1998; 27 Suppl 1:1-41. [PMID: 9638499 DOI: 10.1016/s0901-5027(98)80001-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
MESH Headings
- Acute Disease
- Analgesics/administration & dosage
- Analgesics/pharmacology
- Analgesics/therapeutic use
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/administration & dosage
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Bite Force
- Calcitonin Gene-Related Peptide/analysis
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Evaluation
- Humans
- Mandible/physiopathology
- Mandible/surgery
- Molar, Third/surgery
- Morphine/administration & dosage
- Morphine/pharmacology
- Morphine/therapeutic use
- Movement
- Neuropeptides/analysis
- Pain Threshold/drug effects
- Pain, Postoperative/drug therapy
- Piroxicam/administration & dosage
- Piroxicam/analogs & derivatives
- Piroxicam/pharmacology
- Piroxicam/therapeutic use
- Rats
- Substance P/analysis
- Tooth Extraction/adverse effects
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Affiliation(s)
- S E Nørholt
- Department of Oral and Maxillofacial Surgery, Royal Dental College, Faculty of Health Sciences, University of Aarhus
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34
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Okiji T, Jontell M, Belichenko P, Dahlgren U, Bergenholtz G, Dahlström A. Structural and functional association between substance P- and calcitonin gene-related peptide-immunoreactive nerves and accessory cells in the rat dental pulp. J Dent Res 1997; 76:1818-24. [PMID: 9390474 DOI: 10.1177/00220345970760120301] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Defense mechanisms of the dentin/pulp complex involve a variety of biological systems in which immunocompetent cells, the nervous system, and the vascular supply play important roles. In the present study, pulpal accessory cells were examined regarding (i) their structural relationship to nerves and (ii) how the functional capacities of these cells were affected by neuropeptides. Micro-anatomic association was investigated in the normal rat molar pulp with the use of double-immunofluorescence staining and dual-channel confocal laser scanning microscopy. Examinations of confocal laser scanning microscopic images from single focal planes revealed the presence of apparent contacts between thin, varicose nerve fibers and immunocompetent cells, indicating proximity between these two structures. The close associations were most frequently observed in the para-odontoblastic region of the coronal pulp, where more than 70% of class II antigen-expressing (OX6+) cells showed proximity to nerve fibers immunoreactive to calcitonin gene-related peptide. The corresponding figure for substance P was about 50%. ED2+ macrophages closely associated with nerves were less frequently observed. Functional studies conducted in vitro demonstrated that 10(-9) to 10(-7) mol/L of substance P significantly increased (p < 0.05), while 10(-7) to 10(-6) mol/L of calcitonin gene-related peptide suppressed (p < 0.01) proliferation of purified T-lymphocytes stimulated with sub-optimal concentrations of concanavalin A in the presence of rat incisor pulpal cells as accessory cells. These data suggest that pulpal sensory nerve fibers and their products may have an influence upon the immune defense of the dental pulp.
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Affiliation(s)
- T Okiji
- Department of Endodontology and Oral Diagnosis, Faculty of Odontology, Göteborg University, Sweden
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35
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Inoue H, Muneyuki H, Izumi T, Taguchi K, Nishigawa Y, Watanabe K, Ohkawa Y, Tamura N. Electron microscopic study on nerve terminals during dentin bridge formation after pulpotomy in dog teeth. J Endod 1997; 23:569-71. [PMID: 9587283 DOI: 10.1016/s0099-2399(06)81123-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was designed to examine the relation between pulpal nerves and the differentiation of pulpal cells into preodontoblasts and odontoblasts during the healing process after pulpotomy. A total of 36 upper and lower teeth obtained from six adult dogs were used. The pulp chamber was opened with a sterile diamond bur, the coronal pulp was exposed, and the whole surface of the amputated pulp was capped with calcium hydroxide. The interval between pulpotomy and extraction was 5, 7, 10, 15, 20, 30, 40, 50, and 60 days, and then specimens were examined ultrastructurally. Close contact between fibroblast-like cells/osteoblast-like cells and nerve terminals at the calcification front was observed in the early healing process after pulpotomy, suggesting a close relation between nerve fibers and pulpal cell differentiation.
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Affiliation(s)
- H Inoue
- First Department of Conservative Dentistry, Fukuoka Dental College, Japan
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36
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Pertl C, Amann R, Odell E, Robinson PD, Kim S. Effects of local anesthesia on substance P and CGRP content of the human dental pulp. J Endod 1997; 23:416-8. [PMID: 9587292 DOI: 10.1016/s0099-2399(97)80293-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of the study was to determine immunoreactive Substance P (iSP) and immunoreactive calcitonin gene-related peptide (iCGRP) content in the human dental pulp and whether local anesthesia has an effect on the neuropeptide content. Dental pulps were obtained from patients, who underwent surgical extraction of all 4 impacted wisdom teeth under general isoflurane gas anesthesia. There was a very high interindividual variation in tissue content, with small variation in levels found in teeth from the same patient. Pulps obtained from lower teeth without local anesthesia contained an average of 131 +/- 62 fmol/mg protein of iCGRP and 15 +/- 9 fmol/mg iSP (n = 10). With additional mandibular block anesthesia the values were 194 +/- 71 fmol/mg iCGRP (statistically significant, p = 0.0356, Mann-Whitney-rank-sum-test) and 12 +/- 3.6 fmol/mg iSP. The results suggest that local anesthesia attenuates neuropeptide release in the human dental pulp during surgical extraction.
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Affiliation(s)
- C Pertl
- Department of Oral Surgery, School of Dental, Oral, and Maxillofacial Medicine, Karl-Franzens University of Graz, Austria
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37
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Toriya Y, Hashiguchi I, Maeda K. Immunohistochemical examination of the distribution of macrophages and CGRP-immunoreactive nerve fibers in induced rat periapical lesions. ENDODONTICS & DENTAL TRAUMATOLOGY 1997; 13:6-12. [PMID: 9206382 DOI: 10.1111/j.1600-9657.1997.tb00002.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To clarify the role of calcitonin gene-related peptide (CGRP) in the development of periapical lesions, we examined the distribution of CGRP-immunoreactive (IR) nerve fibers and macrophages, and the behavior of bone tissues in experimentally induced rat periapical lesions by immunohistochemical and quantitative methods. Although no extensive changes were observed at 7 days after pulp exposure, CGRP-IR nerve fibers increased in number until 28 days with a decrease thereafter. These neural changes were closely correlated with the alteration in number of macrophages except on day 7 when macrophages were significantly increased in number as compared with control rats. Tissue repair began to take place and a decrease in number of osteoclasts was observed when the density of CGRP-IR nerve fibers reached a peak. These results suggested that there might be a close relationship between macrophages and CGRP-IR nerve fibers and that CGRP-IR nerve fibers might participate in tissue repair in experimentally induced rat periapical lesions.
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Affiliation(s)
- Y Toriya
- Department of Conservative Dentistry 1, Kyushu University, Fukuoka, Japan
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38
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Hamamoto Y, Nakajima T, Ozawa H, Uchida T. Production of amelogenin by enamel epithelium of Hertwig's root sheath. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1996; 81:703-9. [PMID: 8784903 DOI: 10.1016/s1079-2104(96)80077-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To study the multiple potentials of differentiating odontogenic epithelial cells. STUDY DESIGN Bilateral first and second maxillary molars of 30 immature rats were perforated into the pulp chambers with a round bur. The pulps were observed histologically and immunohistochemically for amelogenin 3, 7, and 14 days after the perforation. RESULTS On day 7, the enamel epithelium of Hertwig's root sheath migrated and formed oval-shaped epithelial islands that resembled epithelial rests of Malassez. On day 14, the islands consisted of epithelial cells with large nuclei and cytoplasm partially surrounded by a subsequently formed osteodentin and cementum. Immunoreactivity for amelogenin was observed in the large epithelial cells and in the area between the cells as well as the calcified tissues. Some of the enamel epithelium resembling columnar ameloblasts of the enamel organ were also positive for amelogenin. CONCLUSIONS The enamel epithelium of Hertwig's root sheath appeared to differentiate into ameloblasts and produce amelogenin.
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Affiliation(s)
- Y Hamamoto
- First Department of Oral and Maxillofacial Surgery, Niigata University School of Dentistry, Japan
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39
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Torneck CD, Kwan CL, Hu JW. Inflammatory lesions of the tooth pulp induce changes in brainstem neurons of the rat trigeminal subnucleus oralis. J Dent Res 1996; 75:553-61. [PMID: 8655759 DOI: 10.1177/00220345960750010701] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Neuroplastic changes are known to occur in the CNS in response to injury of peripheral nerves. Previous investigation has demonstrated neuroplasticity in second-order neurons of the subnucleus oralis (SO) of the trigeminal (V) nuclear complex in association with aseptic injury to the tooth pulp. A question arises, therefore, as to whether similar changes occur in response to injury associated with inflammation induced by tooth pulp infection. The effects of tooth pulp infection on the mechanoreceptive fields (RFs) of SO neurons were examined in rats. Infection was established by exposure and removal of the coronal pulp of the mandibular first molar, which was left open to the oral environment for 7 (n = 5) or 28 (n = 6) days. Neurons in SO were then electrophysiologically characterized in chloralose/urethane-anesthetized rats. The RF and the response properties of 118 low-threshold mechanoreceptive (LTM) neurons from seven-day-old rats and 149 LTM neurons from 28-day-old rats were compared with those of 204 LTM neurons tested in 11 untreated (control) rats. Significant differences were noted in RF size and location when control, seven-day-old, and 28-day-old groups were compared. Radiographic examination revealed inconsistencies among examiners in the interpretation of periapical lesions < 2 mm in diameter and general agreement in the identification of periapical lesions > 2 mm in diameter. Histological examination of teeth with pulp exposure revealed superficial necrosis and inflammation without periapical extension in the seven-day-old animals and total pulp necrosis with periapical inflammation, abscess formation, and alveolar bone resorption in the 28-day-old animals. The results indicate that neuroplastic changes in LTM oralis neurons can develop subsequent to tooth pulp infection and that there may be a correlation between the incidence of these changes and the extension of the attending inflammation from the pulp to the dental supporting tissues.
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Affiliation(s)
- C D Torneck
- Department of Endodontics, Faculty of Dentistry, University of Toronto, ON, Canada
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40
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Holland GR. Periapical neural changes after pulpectomy. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1995; 80:726-34. [PMID: 8680982 DOI: 10.1016/s1079-2104(05)80258-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pulpectomy and pulpal necrosis result in severance of the nerves that supply the pulp as well as loss of their target organ. Inflammatory changes commonly extend into the periapical region to involve those nerves. The neural response to pulpal loss combined with periapical inflammation is a derangement of the periodontal plexus normally located in the center of the periodontal space around the apical third of the root; the result is the formation of a disorganized group of sprouting and branching axons that have some features in common with neuromas. The inflammatory and neural responses continue for at least a year even when pulpectomy is followed by canal debridement and obturation. Then the responses are reduced but not eliminated by steroids. Root canal therapy with techniques that do not leave residual inflammation still results in increased periapical innervation; the increase seems to be an organized addition to the normal periradicular plexus.
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Affiliation(s)
- G R Holland
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan, School of Dentistry, Ann Arbor 48109-1078, USA
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41
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Inoue H, Taniguchi K, Okamura K, Izumi T, Tamura N, Kajiwara S, Yamada K, Kuroda E, Watanabe K, Kitamura K. Ultrastructural relation between nerve terminals and dentine bridge formation after pulpotomy in human teeth. Arch Oral Biol 1995; 40:669-75. [PMID: 7575240 DOI: 10.1016/0003-9969(95)00018-k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Close association between nerve terminals and preodontoblasts, odontoblasts and predentine was observed during healing after pulpotomy. The nerve terminals frequently contained large numbers of synaptic vesicles. Terminals with many vesicles tended to be fewer in the predentine than in the odontoblastic layer. The distribution of terminals was more dense at the stage before the regenerated odontoblasts became arranged regularly beneath the predentine. It is suggested that these terminals have some efferent role(s), especially during collagen synthesis at the early stage of dentinogenesis. The nerves may release their abundant synaptic vesicles, in addition to serving a sensory role for monitoring the increased sensitivity in the injured areas.
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Affiliation(s)
- H Inoue
- First Department of Conservative Dentistry, Fukuoka Dental College, Japan
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42
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Hargreaves KM, Swift JQ, Roszkowski MT, Bowles W, Garry MG, Jackson DL. Pharmacology of peripheral neuropeptide and inflammatory mediator release. ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY 1994; 78:503-10. [PMID: 7528373 DOI: 10.1016/0030-4220(94)90045-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Research conducted in the last 10 years has increased our knowledge on pain mechanisms substantially. Although many local tissue mediators, including neuropeptides, are known to exert pro-inflammatory effects, comparatively little is known about the actual tissue levels of these inflammatory mediators and their pharmacologic regulation. This article describes two new methods, clinical microdialysis and superfusion of dental pulp, which provide data on the pharmacology of peripheral neuropeptide and inflammatory mediator release. Collectively, these methods provide a biochemically based approach toward determining the mechanisms and management of orofacial pain.
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Affiliation(s)
- K M Hargreaves
- Department of Restorative Sciences, University of Minnesota School of Dentistry, Minneapolis
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43
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Holland GR. A histological comparison of periapical inflammatory and neural responses to two endodontic sealers in the ferret. Arch Oral Biol 1994; 39:539-44. [PMID: 7945012 DOI: 10.1016/0003-9969(94)90128-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Previous studies have shown that there is a proliferation of nerves beneath the apices of pulpectomized teeth. This may be due to the inflammation induced after the procedure, resulting, perhaps, from the irritant nature of the materials used to fill the root canal. The experiment reported here was conducted to determine whether this inflammation was induced by the sealer rather than arising as a result of tissue damage and whether, if inflammation is eliminated or reduced, the neural changes are also reduced. In 12 young adult ferrets under general anaesthesia the pulps of the lower canine teeth were removed and replaced with gutta percha and sealer. A sealer of Grossman's formulation with eugenol as the liquid phase was used on one side and a calcium hydroxide sealer that contained no eugenol on the other. Three months later the animals were, again under general anaesthesia, perfused with a fixative mixture. The mandibles were removed and the presence and size of any periapical inflammatory lesions and the density of periapical innervation determined histologically. All 12 teeth sealed with the Grossman's sealer had inflammatory lesions at their apices. Three of the 12 teeth treated with the calcium hydroxide sealer showed similar lesions. In all the teeth with inflammatory lesions the normal arrangement of nerves in a periodontal 'plexus' was disrupted but there was no statistically significant difference between the overall innervation density in inflamed and non-inflamed periapical areas nor between areas beneath teeth sealed with Grossman's sealer and with calcium hydroxide. The incidence of periapical inflammation is related to the nature of endodontic sealer used.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G R Holland
- Department of Restorative Dentistry, Faculty of Dentistry, University of Alberta, Canada
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44
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Yamasaki M, Kumazawa M, Kohsaka T, Nakamura H. Effect of methotrexate-induced neutropenia on rat periapical lesion. ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY 1994; 77:655-61. [PMID: 8065734 DOI: 10.1016/0030-4220(94)90330-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We investigated the effect of methotrexate-induced neutropenia on periapical lesions in rats. Periapical lesions were prepared in all animals by pulpal exposure. The animals were injected with methotrexate three times a week 4 weeks before or after the pulpal exposure. The periapical lesion of each animal was examined histologically, histometrically, and immunohistochemically. The total leukocyte count and neutrophil count in the peripheral blood decreased after the injection. The methotrexate-induced neutropenia elicited after pulpal exposure did not change the status of the periapical lesion, whereas the neutropenia before the exposure inhibited the development of the lesion. Moreover, the neutropenia before pulpal exposure resulted in an inhibition of infiltration of neutrophils into the lesion.
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Affiliation(s)
- M Yamasaki
- Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
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45
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Abstract
Hypersensitive dentine responds to normal changes in touch or temperature with abnormal pain sensations. This paper reviews studies that have shown dynamic changes in sensory nerve structure, cytochemistry and location after tooth injury, suggesting that those changes contribute to dentine hypersensitivity. Nerve fibres containing calcitonin gene-related peptide (CGRP) are the main type of sensory fibre to innervate dentine. Evidence that many of those dentinal nerve endings originate from small myelinated fibres is presented here. The location of CGRP nerve terminals correlates with the pulpal gradients of nerve growth factor that have been demonstrated in normal teeth by in situ hybridization histochemistry. When shallow cavities are drilled into the outer dentine of rat molars a five-to-eight-fold increase in pulpal nerve growth factor precedes the extensive structural changes in the sensory nerve reactions eventually subside if healing occurs, but both continue if inflammation continues. Evidence correlating pulpal inflammation with long-term changes in central trigeminal pain pathways is reviewed. There can be extensive neuroplasticity after tooth injury, both within dental pain fibres and in central pain pathways. The timing of those alterations of nerve structure, location, and cytochemistry is consistent with their involvement in mechanisms of dentine hypersensitivity.
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Affiliation(s)
- M R Byers
- Department of Anesthesiology, University of Washington, Seattle 98195, USA
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46
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Yamasaki M, Kumazawa M, Kohsaka T, Nakamura H, Kameyama Y. Pulpal and periapical tissue reactions after experimental pulpal exposure in rats. J Endod 1994; 20:13-7. [PMID: 8182380 DOI: 10.1016/s0099-2399(06)80020-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of this study was to investigate histologically and histometrically the changes in pulpal and periapical tissues after pulpal exposure in rats. All animals received a pulpal exposure in the left mandibular first molar. Animals were killed at 1 to 56 days after pulpal exposure, and their mandibles were evaluated histologically and histometrically. Histologically, pulpal necrosis extended gradually from the upper part of the pulpal tissue to the apex, with inflammation starting in the periapical tissue at an early stage. As the periapical lesion developed, alveolar bone and cementum resorption was also found. Histometrically, the length of pulpal necrosis increased gradually from 1 to 28 days. The vertical length of the periapical lesion after 14 days was significantly increased, while the horizontal length and the overall area after 7 days were also significantly increased. The periapical lesion extended in a mesiodistal direction at first and then in a vertical direction before expansion ceased.
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Affiliation(s)
- M Yamasaki
- Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
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47
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Oswald RJ, Byers MR. The injury response of pulpal NPY-IR sympathetic fibers differs from that of sensory afferent fibers. Neurosci Lett 1993; 164:190-4. [PMID: 7512246 DOI: 10.1016/0304-3940(93)90889-s] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Light microscopic immunocytochemistry demonstrated that neuropeptide Y (NPY) containing sympathetic fibers in rat molars did not change morphology or staining characteristics after pulp exposure injury. This result, in combination with recent findings concerning NGF synthesis in injured pulp and NGF-receptor localization on pulpal sensory fibers, suggests that small diameter sensory fibers in pulp may be under NGF control, but NPY containing sympathetic efferent fibers are not. Thus, sympathetic fibers in tooth pulp have a different response to NGF compared to those in many other tissues.
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Affiliation(s)
- R J Oswald
- Department of Endodontics, University of Washington, Seattle 98195
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48
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Hong D, Byers MR, Oswald RJ. Dexamethasone treatment reduces sensory neuropeptides and nerve sprouting reactions in injured teeth. Pain 1993; 55:171-181. [PMID: 7906026 DOI: 10.1016/0304-3959(93)90146-g] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Dental injuries have been shown to generate extensive structural and cytochemical changes in sensory fibers that contain neuropeptides such as calcitonin gene-related peptide (CGRP) or substance P (SP). The present study was designed to test whether the anti-inflammatory drug dexamethasone (DEX) can alter neural responses to dental injuries. DEX (20 micrograms/100 g body weight) was given to adult rats (n = 10) prior to dental surgery and daily thereafter for 4 days. Control animals received sterile saline vehicle (n = 6) or no injection (n = 1). Each rat was then anesthetized for dental surgery and a cavity was drilled partway through dentin on the anterior side of the right maxillary first molar. Pulp exposure injuries were also made on two right mandibular molars in 14 of 17 rats. After 4 days of daily drug treatment, the rats were anesthetized and fixed by perfusion with formaldehyde-picric acid, and their jaws were prepared for immunocytochemistry. Neural CGRP immunoreactivity near the maxillary cavity injury site of DEX-treated rats was reduced more than 50% compared to controls, as determined both qualitatively and by digital analysis. The SP immunoreactive (IR) fibers in molar pulp also had extensive inhibition of neural reactions to cavity injury. DEX also reduced the immunoreactivity for CGRP and SP in normal contralateral rat molars of all treated rats, and it caused a postoperative loss of weight. Pretreatment for 1-5 days prior to the 4 day injury gave the same results as pretreatment for 1 h. The mandibular pulp exposure injuries induced a chronic abscess and advancing pulpal necrosis but did not show differences in nerve reactions between DEX-treated rats and the controls. In conclusion, the synthetic steroid dexamethasone suppressed the CGRP and SP neuropeptide immunoreactivity in normal dental nerves and it reduced nerve-sprouting responses to dentin cavity injuries; however, sensory nerve reactions to pulpal exposure injuries were not affected by DEX in these experiments.
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Affiliation(s)
- Dung Hong
- School of Dentistry, University of Washington, Seattle, WA 98105 USA Department of Anesthesiology, University of Washington, Seattle, WA 98105 USA Department of Biological Structure, University of Washington, Seattle, WA 98105 USA Department of Endodontics, University of Washington, Seattle, WA 98105 USA
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49
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Abstract
Patch-clamp recording methods were used to monitor ion currents in tissue-cultured cells derived from human dental pulp. Recordings were made in excised, outside-in or whole-cell patches. In single-channel experiments, the majority of patches contained a high-conductance (approx. 140-180 pS) K(+)-selective ion channel. The probability of the channel being in an open state was dependent on membrane potential, internal calcium and negative pressure applied to the cell membrane. Whole-cell recordings were consistent with these findings; in response to step-wise depolarizations of the cell membrane, most displayed a family of outwardly rectifying, barium-sensitive currents. In addition, a number of patches contained a second class of potassium channel of intermediate (approx. 85-100 pS) conductance, which was largely voltage insensitive and independent of calcium concentration. These results suggest that pulp cells contain a high-conductance potassium channel which probably underlies the outwardly rectifying current found at the whole-cell level. Further, the existence of mechanosensitive channels in these cells raises the possibility that the response to mechanical perturbation of dental pulp may be mediated, in part, by direct effects on odontogenic cells.
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Affiliation(s)
- R M Davidson
- Department of Periodontology, University of Connecticut Health Center, Farmington 06030
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50
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Abstract
This study was intended to clarify the relationship between the neural changes which occur around the apex of the ferret canine after pulpectomy and the inflammatory process induced by the procedure. In 12 young adult ferrets, under general anesthesia, the pulps in the mandibular canine teeth were removed and replaced with gutta percha and Grossman's sealer. Six of the animals were treated with dexamethasone to reduce the inflammatory response. Three months later, the animals, again under general anesthesia, were perfused with a fixative mixture. Three unoperated animals that had not been treated with dexamethasone were also perfused. The mandibular canine teeth and their supporting tissues were removed, processed, and serially sectioned. Three-dimensional reconstructions of the periapical lesions in each animal were assembled and their volumes measured. The density of innervation in the periapical region was estimated. The mean lesion volume in the pulpectomized animals not treated with dexamethasone was 3.54 (+/- 2.27) mm3 and in the dexamethasone-treated animals 1.33 (+/- 1.31) mm3. The differences were statistically significant when tested by the Mann-Whitney U test (p < 0.01). Bacteria were not seen within any of the lesions. The innervation density beneath the canines in the pulpectomized animals not treated with dexamethasone was 164 units per mm2 (+/- 80) and in the steroid-treated animals 151 +/- 68 units per mm2. In the control, untreated animals, the innervation density was 22 +/- 10 units per mm2. The difference between the steroid-treated pulpectomized animals and the untreated pulpectomized animals was not statistically significant (p > 0.5).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G R Holland
- Department of Restorative Dentistry, Faculty of Dentistry, University of Alberta, Canada
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