Clinical Comparison of Eggshell Derived Calcium Hydroxyapatite with Dycal® as Indirect Pulp Capping Agents in Primary Molars

Abstract Objective: To evaluate and compare the efficacy of eggshell derived calcium hydroxyapatite with Dycal® as indirect pulp capping material in primary molars. Material and Methods: A total of 32 carious primary molars from 22 children (6-10-years) were screened, of which 26 primary molars meeting inclusion criteria were selected and equally divided into two groups. At the first appointment, the infected dentin was excavated using a spoon excavator after treating the carious part with Carie-Care™ chemomechanical caries removal agent. After this, eggshell derived calcium hydroxyapatite in Group 1 and Dycal® in Group 2 were used as liners followed by restoration of the cavity with type IX glass ionomer cement. Clinical assessment for pain and radiographic assessment for measurement of the amount of reparative dentin thickness formation was performed at baseline, 8 weeks and 3 months. The data were subjected to statistical analysis by one-way ANOVA and Kruskal-Wallis tests. Results: Higher mean reparative dentin formation was found in eggshell derived calcium hydroxyapatite group than Dycal® group at the end of 8 weeks and 3 months and the difference was significant statistically (p<0.001). Conclusion: Eggshell derived calcium hydroxyapatite seems to be a suitable alternative to Dycal® (calcium hydroxide) that can be used as a liner for indirect pulp capping in primary molars.

Mesenchymal dental pulp cells attenuate dentin resorption in homeostasis.

Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone-derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal resorption in the root canal, pulp/dentin regeneration, and root resorption in orthodontic tooth movement.

Histologic evaluation of human pulp tissue after orthodontic intrusion.

INTRODUCTION: The forces applied during orthodontic treatment bring about effects on the teeth and surrounding tissues. The aim of this study was to evaluate the possible changes in the human pulpal tissue resulting from orthodontic intrusion in a 21-day period using histologic examination. METHODS: The sample consisted of 17 young individuals of both sexes between the ages of 12 and 19 years. A total of 34 premolars were evaluated with orthodontic indication of extraction. Because it is a split-mouth study, in each patient, intrusion force of 60 g was applied randomly on 1 of the dental elements experimental group for 21 days. The counterpart control group received no force. After extractions, these dental elements were fixed in 10% formaldehyde, processed automatically, submitted to histotechnical preparation, and stained with hematoxylin-eosin for analysis under optical microscope. RESULTS: The paired Fisher exact test (P ≤ .05) showed a significant increase of fibrous tissue in the experimental group. The nonparametric paired Wilcoxon test (P ≤ .05) showed a significant increase in the number of pulpal nodules in the elements of the experimental group and showed no difference in the number of blood vessels between the groups. Large-caliber vessels and congested elements were observed in 8 of the experimental group elements. CONCLUSIONS: The orthodontic intrusion force, in these conditions, caused vascular changes in the pulpal tissue and also increased the presence of fibrosis and the number of pulp calcifications in the experimental elements.

Histologic examinations of teeth treated with 2 scaffolds: a pilot animal investigation.

INTRODUCTION: A growing body of evidence is building a case for the possibility of tissue regeneration within the root canal of necrotic teeth, allowing for continued root development. However, it remains unknown what type of tissue is produced after regenerative endodontics. The purpose of this study was to use blood clots and platelet-rich plasma (PRP) as scaffolds in regenerative endodontics under ideal conditions in a ferret model to examine the tissues generated within the root canals. METHODS: The pulps of 21 canine teeth from 7 young ferrets were extirpated using broaches without filing the canal walls. Bleeding was stimulated from the periapical tissues, and a blood clot was induced in the canal space to the level of the cementoenamel junction in 12 teeth. PRP was prepared and placed in the canals to the level of the cementoenamel junction in 9 teeth. The coronal access was sealed with mineral trioxide aggregate. Seven canines were not operated on and served as controls. Three months later, block sections including each canine and its surrounding tissues were removed for histologic evaluation. The tissues found in the canals of experimental teeth were compared with those in the control teeth. RESULTS: Almost all of the experimental teeth showed the presence of intracanal bonelike tissue. No evidence of dentinal wall thickening or apical narrowing was noted in the experimental teeth. CONCLUSIONS: In this experimental model, the use of either PRP or blood clots during regenerative endodontics leads to the formation of intracanal bonelike tissue without continual root maturation.

Preliminary study on dental pulp stem cell-mediated pulp regeneration in canine immature permanent teeth.

INTRODUCTION: The health of human teeth depends on the integrity of the hard tissue and the activity of the pulp and periodontal tissues, which are responsible for nutritional supply. Without the nourishing of the pulp tissue, the possibility of tooth fracture can increase. In immature permanent teeth, root development may be influenced as well. This study explored the potential of using autologous dental pulp stem cells (DPSCs) to achieve pulp regeneration in a canine pulpless model. METHODS: The establishment of the pulpless animal model involved pulp extirpation and root canal preparation of young permanent incisor teeth in beagles. Autologous DPSCs were obtained from extracted first molars and expanded ex vivo to obtain a larger number of cells. The biological characteristics of canine DPSCs (cDPSCs) were analyzed both in vitro and in vivo by using the same method as used in human DPSCs. cDPSCs were transplanted into the pulpless root canal with Gelfoam as the scaffold, and root development was evaluated by radiographic and histologic analyses. RESULTS: cDPSCs with rapid proliferation, multiple differentiation capacity, and development potential were successfully isolated and identified both in vitro and in vivo. After they were transplanted into the pulpless root canal with Gelfoam as the scaffold, DPSCs were capable of generating pulp-like tissues containing blood vessels and dentin-like tissue. Thickening of the root canal wall was also observed. CONCLUSIONS: This study demonstrates the feasibility of using stem cell-mediated tissue engineering to realize pulp regeneration in immature teeth.

Responses of immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures.

AIM: To report several types of response of immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscess to revascularization procedures. METHODOLOGY: Twenty immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscesses from 20 patients were included. The teeth were isolated with rubber dam, and pulp chambers was accessed through the crowns. The canals were gently irrigated with 5.25% sodium hypochlorite with minimal mechanical debridement. Calcium hydroxide was used as an inter-appointment intracanal medicament and placed into the coronal half of the canal space. After resolution of clinical signs and symptoms, bleeding was induced into the canal space from the periapical tissues using K-files. The coronal canal space was sealed with a mixture of mineral trioxide aggregate (MTA) and saline solution. The access cavity was filled with composite resin. These immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscesses were followed up from 6 to 26 months. RESULTS: Five types of responses of these immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures were observed: type 1, increased thickening of the canal walls and continued root maturation; type 2, no significant continuation of root development with the root apex becoming blunt and closed; type 3, continued root development with the apical foramen remaining open; type 4, severe calcification (obliteration) of the canal space; type 5, a hard tissue barrier formed in the canal between the coronal MTA plug and the root apex. CONCLUSIONS: Based on this case series, the outcome of continued root development was not as predictable as increased thickening of the canal walls in human immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess after revascularization procedures. Continued root development of revascularized immature permanent necrotic teeth depends on whether the Hertwig's epithelial root sheath survives in case of apical periodontitis/abscess. Severe pulp canal calcification (obliteration) by hard tissue formation might be a complication of internal replacement resorption or union between the intracanal hard tissue and the apical bone (ankylosis) in revascularized immature permanent necrotic teeth.

Response of human dental pulp to calcium hydroxide paste preceded by a corticosteroid/ antibiotic dressing agent

Aim: To evaluate the treatment with corticosteroid/antibiotic dressing in pulpotomy with calciumhydroxide. Methods: Forty-six premolars were pulpotomized and randomly assigned into 3groups. In Group I pulpal wound was directly capped with calcium hydroxide, and Group II and Group III received corticosteroid/antibiotic dressing for 10 min or 48 h, respectively, before pulp capping. Teeth were processed for histological analysis after 7, 30 or 60 days to determine inflammatory cell response, tissue disorganization, dentin bridge formation and presence of bacteria.Attributed scores were analyzed by Kruskal-Wallis and Mann-Whitney tests (á=0.05). Results:On the 7th day, all groups exhibited dilated and congested blood vessels in the tissue adjacent to pulpal wound. The inflammatory cell response was significantly greater in Group III (p<0.05). On the 30th day, in all groups, a thin dentin matrix layer was deposited adjacent to the pulpal wound and a continuous odontoblast-like cell layer underlying the dentin matrix was observed. On the60th day, all groups presented a thick hard barrier characterized by an outer zone of dystrophic calcification and an inner zone of tubular dentin matrix underlined by a defined odontoblast-like celllayer. Conclusions: Within the limitations of present study, considering that the treatment was performed in healthy teeth, it may be concluded that the use of a corticosteroid/antibiotic dressing before remaining tissue protection with calcium hydroxide had no influence on pulp tissue healing.

Clinical, radiographic, and histopathologic evaluation of Nd:YAG laser pulpotomy on human primary teeth.

The purpose of this study was to compare clinical, radiographic, and histopathologic effects of Nd:YAG laser pulpotomy to formocresol pulpotomy on human primary teeth. Patients with at least two vital primary molar teeth that required pulpotomy, because of pulpal exposure to caries, were selected for this study. After hemorrhage control, complete hemostasis into the canal orifice was achieved by exposure to Nd:YAG laser (1064 nm) and an He-Ne laser (the aiming beam of the Nd:YAG laser) in noncontact mode at 2 W, 20 Hz, 100 mJ, or was achieved by applying 1:5 dilution of formocresol. Forty-two teeth in two groups were to be followed up clinically and radiographic at 1, 3, 6, 9, and 12 months. Eighteen teeth planned for serial extractions were selected for histopathologic study. The teeth were extracted at 7 and 60 days. The teeth in the laser group had a clinical success rate of 85.71% and a radiographic success rate 71.42% at 12 months. The teeth in the formocresol group had a clinical and radiographic success rate of 90.47% at 12 months. There were no statistically significant differences between laser and formocresol group with regard to both clinical and radiographic success rates. There was a statistically significant difference between 7- and 60-day laser groups with regard to inflammatory cell response criteria. Dentin bridge was absent in all samples. No stained bacteria were observed in any of these samples. In conclusion, Nd:YAG laser may be considered as an alternative to formocresol for pulpotomies in primary teeth.

A histopathologic study of direct pulp-capping with adhesive resins.

OBJECTIVE: The purpose of this study was to evaluate the histologic pulp responses of Optibond and Syntac adhesive resin systems placed directly on exposed pulp tissues. STUDY DESIGN: Class V facial cavities with pulpal exposures were prepared in dogs. After acid etching of enamel margins, the cavities were restored with a composite resin after pulp-capping with one of the dentin bonding agents. The remaining exposures were capped with calcium hydroxide and amalgam as controls. The animals were killed after 7, 21, and 90 days and the pulps were evaluated histologically. Statistical analysis was carried out with the chi-square test. RESULTS: There was no statistically significant difference with respect to inflammatory cell response, fibrosis, bleeding, or bacterial staining criteria over the time intervals of evaluation among the Optibond, Syntac, and calcium hydroxide groups. New dentin formation was also observed for all of the groups at the end of 90 days. CONCLUSION: The results of direct pulp-capping with a dentinal adhesive and composite resin appear promising but further in vivo studies are recommended.

Progressive changes in the pulpo-dentinal complex and their clinical consequences.

With changes in the age structure and oral health in the population, changes in the pulpo-dentinal complex are becoming more relevant clinically. Age-related changes in the structure of dentine and pulp are reviewed. The influence of these changes on restorative dentistry are considered with particular emphasis on endodontics and the use of adhesive restorative materials.

Human pulp response after partial pulpotomy with two calcium hydroxide products.

Twenty human permanent teeth were used to study the pulpal response of two calcium hydroxide products, Dycal and Pulpdent Multi-Cal, after partial pulpotomy. Teeth were extracted at 4 months, fixed, and prepared for histologic examination. All 10 teeth treated with Dycal showed complete soft tissue healing and bridge formation. No stained bacteria were seen throughout the serial sections. One tooth treated with Dycal showed acceptable histologic results, dentin deposition in the root canal. Six cases dressed with Pulpdent Multi-Cal showed acceptable histologic results, whereas four teeth showed severe inflammation or necrosis associated with bacterial penetration into the pulp tissue. Clinically, one tooth treated with Pulpdent Multi-Cal showed pulpal pain and was extracted at 90 days. Our data support the thesis that human permanent pulps will promote tissue healing and dentin bridge formation as long as bacterial microleakage is excluded.

Rate of formation of tertiary dentin in dogs' teeth in response to lining materials.

The rate of tertiary dentin produced in response to four lining materials placed in standardized cavities in dogs' teeth was measured over a period of 119 days. Sterile denatured dentin ash was used as a control material in an attempt to quantify tertiary dentin formation in response to cavity preparation. In all periods the amounts of tertiary dentin formed beneath the control material were significantly smaller than those formed beneath any of the four lining materials. In the first 98 days the rate of formation of tertiary dentin beneath calcium hydroxide (Calxyl) was significantly greater than that beneath the material containing corticosteroid (Ledermix cement). In the last 21 days there was no difference in daily rates of tertiary dentin production beneath all of the lining materials. With all the lining materials there was a highly significant difference between the daily amounts of tertiary dentin formed in the first 6 weeks and those in the last 11 weeks.

The tissue reactions after capping of dog teeth with calcium hydroxide experimentally crammed into the pulp space.

The pulps of 48 permanent dog teeth, incisors and canines, were evaluated histopathologically after capping treatment with pure calcium hydroxide placed by two methods: the experimental method, in which the calcium hydroxide was crammed into the pulpal space via the exposure site, and the usual method of direct pulp capping (controls). The results were recorded after periods of 2, 15, and 69 days. The healing process with hard-tissue formation was more evident in the experimentally capped teeth, despite the fact that pulpal necrosis occurred in a higher proportion of these teeth after use of this method of placement of the calcium hydroxide.

The effect of inferior alveolar nerve resection on dentin formation.

The purpose of this investigation was to quantitatively evaluate the effects of inferior alveolar nerve resection on dentinal structures of dogs with the use of fluorescent tissue-time markers. After resection of the mandibular right inferior alveolar nerve and an experimental interval of 70 days, dentin formation was determined from serial cross sections through the mandibular canines. Results indicated that denervation did not appear to affect secondary dentin formation in the canine teeth of dogs.

Pulp response after calcitonin treatment of direct exposures in the dog.

The hypocalcemic hormone, calcitonin, was used in directly pulp-capped teeth to determine whether or not calcitonin promoted healing. Two dogs were used. Twelve teeth received the calcitonin; nine control teeth were prepared, and five were treated with calcium hydroxide. Calcitonin did not increase either the rate of healing or the amount of secondary dentin formed. Calcitonin reduced the degree of inflammation in the treated tooth pulps.

Aberrations in pulpal histology and dentinogenesis in transplanted erupting teeth.

Responses of pulpal tissues were assessed histologically in teeth that had been transplanted after root formation was moderately well advanced. Degeneration occurred in the coronal third, but the area was repopulated by cells proliferating from the center of the pulp. Apically, the tissues, including the odontoblasts, remained vital and functional. Widespread intrapulpal formation of osteodentin was prominent in later observation periods. Apical closure occurred prematurely by production of osteodentin and cellular cementum in the form of an apical diaphragm; these mineralized tissues were confluent with a similarly active deposition of cellular cementum apically on the root surface.

The pulpal response to citric acid in cats.

Citric acid conditioning of dentine has been proposed as an efficacious treatment for promoting re-attachment after periodontal surgery. This study investigated the pulpal reactions to periodontal surgery combined with citric acid (pH 1) demineralization of exposed dentine for 3 min. 9 cats were used as the experimental animals, with each cat providing 1 negative and 1 positive control and 2 experimental canine teeth. Evaluation was over 3 observation periods, with 3 cats in each period being sacrificed at 4, 21 and 83 days. Positive control teeth, which underwent periodontal surgery combining the removal of approximately 3 mm2 of labial bone and vigorous root planning of the exposed root surfaces, displayed mild to moderate pulpal reactions during the short- and intermediate-term periods and only mild to no reactions in the long-term period. The addition of citric acid demineralization, however, resulted in 5 experimental teeth (28%) becoming abscessed or totally necrotic in the intermediate- and long-term periods. At 21 days, the frequency of adverse pulpal responses to surgery and citric acid conditioning was significantly (p less than 0.05) greater than to surgery alone. Although 4 experimental teeth were relatively uninflamed at the long-term period of observation, all showed irritational dentine formation. Penetration of exposed dentinal tubules by plaque bacteria was observed only in the citric acid treated teeth.

Intentional replantation to prevent predictable endodontic failures.

A clinical approach to intentional replantation with indications and contradictions is presented. A histopathologic analysis of a tooth that was replanted and then removed 22 years later is illustrated.