THE EFFECTS OF SURGICAL EXPOSURES OF DENTAL PULPS IN GERM-FREE AND CONVENTIONAL LABORATORY RATS.
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Dental Pulp↗
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DENTAL PULP HEMOGRAM.
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Blood Cell Count↗
The effects of surgical exposures of dental pulps in germfree and conventional laboratory rats.
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Dental Pulp Exposure↗
Effects of pulpal exposure in the primary dentition on the succedaneous teeth.
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Animals↗
Characteristics and effects of calcified degenerative zones on the formation of hard tissue barriers in amputated canine dental pulp.
The purpose of this research was to study under undecalcified conditions the presence, ultrastructural features, and contributions of the degenerative zone beneath the necrotic zone and whether it had effects on the formation of reparative dentin in canine incisors and premolars. The research was conducted over a period of 14 days after experimental pulpotomy using calcium hydroxide as a pulp-capping agent. On the first day following pulp exposure and capping with calcium hydroxide, electron-dense spherical bodies were observed under the necrotic zone. Energy dispersive X-ray point analysis confirmed that these electron-dense deposits contained calcium and phosphorus. By the third day, varying amounts of minute von Kossa-positive granules could be observed light-microscopically between the two zones of necrosis and underlying vital pulp tissue. Migration and proliferation of pulpal cells, most probably mesenchymal cells, were observed adjacent to the von Kossa-positive zone. The ultrastructure of the von Kossa-positive zone consisted of degenerated cells, electron-dense spherical bodies, and electron-dense shortened dilating fibrils. By the seventh day, short cylindrical-shaped cells collected at the coronal end of the vital pulp tissue. By the fourteenth day, the specimens having a uniform von Kossa-positive zone exhibited rapid differentiation of odontoblasts and tubular dentin formation. In contrast, only some specimens having an irregular von Kossa-positive zone exhibited osteodentin formation and the beginning of odontoblast differentiation beneath the osteodentin. These findings suggest that this calcified degenerative zone has an important effect on the reparative process of pulp tissue after pulpotomy.
Animals↗
[Comparative light microscopy study of periapical and pulpal response to different stimuli (1)].
A comparative study of pulpal and periapical responses to pulpal exposure and electric stimulus. In this report we communicate the changes found in the pulp and supporting tissues.
Animals↗
Traumatic crown fractures in permanent incisors with immature roots: a follow-up study.
A follow-up study of crown fractured permanent incisors with incomplete root formation was carried out in a group of patients, aged 6-12 years, over a 5-year period in the Dental Clinic of the University of Verona, Italy. The number of injured patients was 55, representing 84 injured incisors. All patients were followed clinically and radiographically using a standardized follow-up protocol. The most common type of trauma was fracture of enamel and dentine without pulpal exposure (80%) and the most common type of treatment was restoration with the acid-etch composite resin technique (46%). Bonding of the crown fragment was performed in 10 instances (12%). At the 5-year-control all teeth with fracture of the enamel had no pulp complications. Four of 67 teeth (6%) with fracture of the enamel and dentine without pulpal involvement showed pulp necrosis and 1 tooth showed pulp obliteration (1.5%). Eight of 14 teeth (57%) with fractures of the enamel and dentine with pulp involvement showed pulp necrosis. Aesthetically 36 of the restored teeth were deemed satisfactory (43%). In 9 teeth the bonded fragment had to be rebonded. 14 teeth were considered unsatisfactorily restored due to wear of the composite (17%). 34 restored teeth had to be retreated because of a new trauma (40%). In one tooth a previous bonded fragment had to be rebonded. These results confirmed that crown fractures without pulp involvement in permanent incisors with incomplete root formation hav a low percentage of pulp complications, while 60% of the teeth with crown fractures with pulp involvement had pulp complications.
Chi-Square Distribution↗
Long-term prognosis of crown-fractured permanent incisors. The effect of stage of root development and associated luxation injury.
OBJECTIVES: The aim of the present study was to investigate pulp healing responses following crown fracture with and without pulp exposure as well as with and without associated luxation injury and in relation to stage of root development. PATIENT MATERIAL AND METHODS: The long-term prognosis was examined for 455 permanent teeth with crown fractures, 352 (246 with associated luxation injury) without pulpal involvement and 103 (69 with associated luxation injury) with pulp exposures. Initial treatment for all patients was provided by on-call oral surgeons at the emergency service, University Hospital (Rigshospitalet), Copenhagen. In fractures without pulpal involvement, dentin was covered by a hard-setting calcium hydroxide cement (Dycal), marginal enamel acid-etched (phosphoric acid gel), then covered with a temporary crown and bridge material. In the case of pulp exposure, pulp capping or partial pulpotomy was performed. Thereafter treatment was identical to the first group. Patients were then referred to their own dentist for resin composite restoration. RESULTS: Patients were monitored for normal pulp healing or healing complications for up to 17 years after injury (x = 2.3 years, range 0.2-17.0 years, SD + 2.7). Pulp healing was registered and classified into pulp survival with no radiographic change (PS), pulp canal obliteration (PCO) and pulp necrosis (PN). Healing was related to the following clinical factors: stage of root development at the time of injury, associated damage to the periodontium at time of injury (luxation) and time interval from injury until initial treatment. Crown fractures with or without pulp exposure and no concomitant luxation injury showed PS in 99%, PCO in 1% and PN in 0%. Crown fractures with concomitant luxation showed PS in 70%, PCO in 5% and PN in 25%. An associated damage to the periodontal ligament significantly increased the likelihood of pulp necrosis from 0% to 28% (P < 0.001) in teeth with only enamel and dentin exposure and from 0% to 14% (P < 0.001) in teeth with pulp exposure. CONCLUSIONS: In the case of concomitant luxation injuries, the stage of root development played an important role in the risk of pulp necrosis after crown fracture. However, the primary factor related to pulp healing events after crown fracture appears to be compromised pulp circulation due to concomitant luxation injuries.
Adolescent↗
Identification of hierarchical factors to guide clinical decision making for successful long-term pulp capping.
OBJECTIVE: Clinicians have few quantitative studies that rank the in vivo pulp capping effects of commonly used restorative materials. These factors were investigated to provide guidance to clinicians. METHOD AND MATERIALS: One hundred sixty-one standardized pulp-exposed cavities were prepared in nonhuman primate teeth. Exposed pulps were capped with calcium hydroxide, resin-modified glass-ionomer cements, and resin composites. Teeth were collected from 7 to 720 days to observe a full range of responses. Pulpal reactions were categorized according to the standards set by the International Standards Organization. Bacteria were detected with McKay's stain. RESULTS: The incidence of bacterial microleakage was 19.7% with resin composite, 21.1% with resin-modified glass-ionomer cement, and 47.0% with calcium hydroxide. The severity of pulpal inflammation increased with the presence of bacteria or tunnel defects. The severity of pulpal inflammation prevented dentinal bridge formation at varying levels: slight for resin composite and resin-modified glass-ionomer cement, and severe with calcium hydroxide. The incidence of severe inflammation or pulpal necrosis was 7.9% with resin composite, 10.6% with calcium hydroxide, and 10.5% with resin-modified glass-ionomer cement. Other variables, such as pulpal exposure width and tertiary dentin formation, were not highly correlated to pulpal inflammation. CONCLUSION: Pulp capping with resin composite provided the lowest incidence of bacterial microleakage, the lowest levels of pulpal inflammation, and the lowest incidence of necrosis.
Analysis of Variance↗
Replacement of a fractured incisor fragment over pulpal exposure: a long-term case report.
This article presents the long-term follow-up of a patient in whom an incisor that had been fractured through the pulp was replaced with the original tooth fragment. In the replacement process, the enamel, dentin, and pulp were acid etched and bonded as part of the restoration protocol. More than 5 years have passed since the original treatment, and the treatment has thus far been a success.
Adolescent↗
The mechanism of pulpal wound healing.
The favourable response of exposed pulp tissue against a variety of materials used for pulp capping in experimental conditions, as observed by hard tissue (reparative dentine) formation, demonstrates an intrinsic capacity of pulp tissue for healing. However, in the clinical situation, in which a pulpal exposure is usually accompanied by a long-term external irritation with the subsequent long-term inflammatory response to that irritation, the outcome of pulp capping procedures is not as predictable. While some of the factors related to the defensive reactions and healing after pulp exposure and capping procedures are well understood, the mechanisms and importance of others remain less well-known. Understanding the mechanisms regulating the spread of inflammation and necrosis in pulp tissue, and the factors regulating healing after closure of the wound, would facilitate the development of new and better treatment procedures with more predictable outcomes. In this review, some of the aspects considered to be important in pulpal wound healing are discussed.
Animals↗
A clinical study of direct pulp capping applied to carious-exposed pulps.
Direct pulp capping of carious-exposed pulp was performed on 44 teeth. We evaluated the success rates of these cases, and analyzed the relationships between the success rates and their clinical findings. Furthermore, we examined the length of time necessary for adequate postoperative follow-up. The success rate in this study was 81.8%. Age of the patients, type of teeth, responses to thermal stimuli and percussion, and the diameter of pulpal exposure had no bearing on the success rate. However, the degree of bleeding on pulpal exposure was related to the success rate (p = 0.042). The success rates of cases in which postoperative follow-up periods were 3 to 18 months were similar (80 to 83%), whereas those with follow-up for 21 months (91.7%) and 24 months (100%) showed higher success rates. These results showed that direct pulp capping was applicable to carious-exposed pulp, and the degree of bleeding is indicative of the prognosis of this treatment. The length of time necessary for adequate postoperative follow-up was suggested to be 21 months.
Adult↗
An in vivo evaluation of hemorrhage control using sodium hypochlorite and direct capping with a one- or two-component adhesive system in exposed nonhuman primate pulps.
OBJECTIVE: This study evaluated the biologic ability of sodium hypochlorite to control hemorrhage via chemical amputation of the coagulum, to remove dentin chips, to assist healing, and to facilitate formation of a dentinal bridge under two adhesive systems. METHOD AND MATERIALS: Ninety Class V cavities with mechanical pulpal exposures were placed in the teeth of five adult monkeys and histologically observed. All exposures were prepared with a No. 330 bur, and hemorrhage was controlled with 3% sodium hypochlorite. Twenty-two exposures were capped with All-Bond 2 and AElitefil, and 26 exposures were capped with One-Step (OS) and Resinomer (RS). Two pulps were excluded from the final data. Forty-two exposures were capped with calcium hydroxide and amalgam as controls. At 7, 27, and 90 days, tissues were obtained by perfusion fixation, demineralized, sectioned, stained, and histologically graded according to published qualitative criteria. RESULTS: For both adhesives, at 7 days, 12 of 16 pulps showed no coagulum remnants or dentin chips at the material interface. No necrotic pulps were observed. At 27 and 97 days, 26 of 30 capped pulps had dentinal bridges at the adhesive interface. Reparative dentin was present in 28 pulps. Four 97-day pulps exhibited necrosis associated with stained bacteria. One 97-day pulp contained dentin chips throughout the pulp and demonstrated no healing, no reparative dentin, and no stained bacterial profiles. CONCLUSION: Normal soft tissue reorganization and dentinal bridge formation were observed in 86% of pulps treated with sodium hypochlorite and either adhesive system.
Animals↗
Pulpal evaluation of two adhesive systems in rat teeth.
Formocresol is the agent most frequently used with pulpotomies in primary teeth, but its use is currently under discussion in regard to its possible toxic effects. Some current works suggest the use of dentinal adhesives in cavities with minimal dentinal thickness and even in small pulpal exposures. Our objective was to evaluate pulpal response to the application of two dentinal adhesives Syntac and Prime & Bond NT in pulpal exposures in rat teeth. Sprague Dawley rats were used, male, 150 to 200 gm in weight. The maxillary first molar, left and right, was employed in each case, a total of twelve teeth. Duration of the study was 45 days. Sections were evaluated using a light microscope in order to determine pulpal response to the two adhesives. In both groups the persistence of chronic inflammation was associated with the absence of dentinal bridges in the affected specimens. Areas of necrosis and absence of regularity of the odontoblastic layer could also be seen.
Animals↗
Periapical tissue reactions after pulp exposure in rat molars.
Apical periodontal lesions were produced in the rat molar by exposing the pulp to the oral environment. The natural history of the undisturbed lesion was studied at time intervals ranging from 2 days to 1 year postoperatively. The earliest reactions were usually inflammatory infiltration at the apex. The severity of the lesions was related to the amount of vital pulp still present in the tooth rather than to the time lapse after exposure. After 1 month most pulps has undergone necrosis and the lesions about the apices which followed showed two main types of reaction. In the case of the suppurative reaction, pus drained along a root surface, destroying the periodontal ligament and interradicular bone until it emerged at the gingival sulcus. The sinus tract could become lined with oral epithelium. In the reparative type of reaction, suppuration was absent or minimal and the apices were surrounded by fibrous connective tissue. The fiber bundles occasionally formed a collagenous scar, but they were usually replaced by cementum and bone with a new periodontal ligament. The width of the periodontium was never restored to its normal dimensions. Secondary destruction of the teeth occurred by fracture of cusps followed by caries which started in the exposed pulp chamber. Despite the predominance of destructive factors, spontaneous repair indicated good healing potential of the apical periodontal tissues.
Animals↗
Effect of methotrexate-induced neutropenia on pulpal inflammation in rats.
The purpose of this study was to determine the role of neutropenia in pulpal inflammation. We investigated the effect of methotrexate-induced neutropenia on pulpal inflammation in rats. Pulpal inflammation was produced by pulpal exposure. Thirty-six rats were divided equally into control and experimental groups. The control animals received no injection, whereas the experimental animals were injected with 7.5 mg/kg of methotrexate once a day for 3 days before the pulpal exposure. The pulp was exposed in the mandibular first molar of all animals, and the exposed areas were left open. Animals were killed at 2, 4, and 7 days thereafter. Before they were killed, peripheral blood was taken. The number of total leukocytes and neutrophils in the peripheral blood of experimental animals was significantly decreased compared with those of control animals. The methotrexate-induced neutropenia resulted in the initiation of a bacterial invasion into the pulpal tissue and an increase in pulpal necrosis, as well as lessened abscess formation. Histometrically, the area of pulpal necrosis in experimental animals was significantly greater than that in the control animals. Immunohistochemically, the neutropenia resulted in inhibition of the infiltration by neutrophils. These results suggest that the neutrophil plays an important role in the defense against bacteria in pulpal tissue.
Animals↗
Endodontic diagnosis. Mystery or mastery?
UNLABELLED: Review of 6 clinical distinctions: (1) Symptom: "anything under the sun." DIAGNOSIS: pulp exposure. Duplicate: clinical or radiographic pulp exposure evidence. TREATMENT: endodontics or pulp cap under strict protocol conditions. (2) Symptom: "cold." DIAGNOSIS: hyperemia. Duplicate: ice. TREATMENT: pulp protection or endodontics. (3) Symptom: "heat." DIAGNOSIS: pulpitis. Duplicate: heat. TREATMENT: pulpotomy for multirooted teeth or pulpectomy for single-rooted teeth. Schedule endodontic completion. (4) Symptom: "I recently had a toothache and now it is gone." DIAGNOSIS: necrosis. Duplicate: Electric Pulp Test and ice are negative. TREATMENT: endodontics. (5) Symptom: "I had a toothache awhile back and now it is gone." DIAGNOSIS: LEO. Duplicate: Electric Pulp Test, ice, and test cavity are negative. TREATMENT: endodontics. (6) Symptom: "It really hurts to touch my tooth." DIAGNOSIS: percussion. Duplicate: may or may not have a LEO and may or may not have cellulitis. TREATMENT: reduce occlusion, access cavity, water chew, and schedule to finish endodontics. If these tests are carefully performed, then they are objective and the doctor does not have to be in a subjective situation. A newfound sense of endodontic diagnostic mastery is experienced. Perhaps the best way to summarize the simplicity of this clinical diagnostic scheme is to quote Sherlock Holmes: "Nothing is more deceptive than the obvious."
Dental Pulp Diseases↗
Tunnel defects in dentin bridges: their formation following direct pulp capping.
This study was conducted to observe the formation and nature of tunnel defects in dentin bridges, assess the nature of the associated soft tissue elements, and note the relationship of pulp inflammation and necrosis associated with these defects. A total of 235 teeth with class 5 cavity preparation exposures were randomly distributed throughout the dentitions of 14 adult rhesus monkeys. Each pulp was exposed and left open to the oral microflora at one of four time intervals, flushed with saline, debrided, capped with one of two hard-set calcium hydroxide medicaments [Ca(OH)2 (Dycal or Life)] and restored with a dispersed-phase amalgam alloy. Observation times were 14 days, 5 weeks, and 1 and 2 years. A total of 192 dentin bridges formed against the Ca(OH)2 medicaments Life or Dycal in 235 pulp-capped teeth. Considering all four capping periods, 89% of all dentin bridges contained tunnel defects (172 of 192). Forty-one percent (78) of the 192 dentin bridges were associated with recurring pulp inflammation or necrosis and were always associated with the presence of inflammatory cells and stained bacterial profiles. This study demonstrates that a statistically significant number of dentin bridges contain multiple tunnel defects, most of which appear to remain patent. These patent tunnels fail to provide a hermetic seal to the underlying pulp against recurring infection due to microleakage. Most Ca(OH)2 medicaments have been reported to disintegrate and wash out after 6 months, leaving a void underneath the restoration and thereby a pathway for bacterial infection. This study reemphasizes the need to employ biologically relevant measures that will provide a long-term clinical seal against microleakage following direct pulp capping with Ca(OH)2 medicaments alone.
Animals↗