Application Of Calcium Hydroxide Research Articles

The effects of short-term application of calcium hydroxide on dentin fracture strength

Objectives: This in vitro study investigated whether short-term application of calcium hydroxide in the root canal system for 1 and 4 wk affects the fracture strength of human permanent teeth. Materials and Methods: Thirty two mature human single rooted mandibular premolars in similar size and dentin thickness without decay or restorations were hand and rotary instrumented and 16 teeth vertically packed with calcium hydroxide paste and sealed coronally with caviton to imitate the endodontic procedure and the other 16 teeth was left empty as a control group. The apicies of all the samples were sealed with resin, submerged in normal saline and put in a storage box at 37℃ to mimic the oral environment. After 1 and 4 wk, 8 samples out of 16 samples from each group were removed from the storage box and fracture strength test was performed. The maximum load required to fracture the samples was recorded and data were analysed statistically by the two way ANOVA test at 5% significance level. Results: The mean fracture strengths of two groups after 1 wk and 4 wk were similar. The intracanal placement of calcium hydroxide weakened the fracture strength of teeth by 8.2% after 4 wk: an average of 39.23 MPa for no treatment group and 36.01 MPa for CH group. However there was no statistically signif- icant difference between experimental groups and between time intervals. Conclusions: These results suggest that short term calcium hydroxide application is available during endodontic treatment. ABSTRACT 1 Shin EJ, Dental school student, Chonnam National University School of dentistry,

An interesting healing outcome of a replanted immature permanent tooth: a case report

A case of an avulsed upper left central incisor that was replanted after 3 h in a 7-year-old girl is presented. The tooth showed signs of an acute periapical abscess at 2 weeks after replantation. Apexification with mineral trioxide aggregate (MTA) following application of calcium hydroxide was attempted. At 3-year and 6-month follow-up, the tooth was asymptomatic with adequate clinical function. The radiograph showed resolution of the periapical lesion and apparent radiopaque tissue under MTA plug resembling root end morphology.

Management of teeth with necrotic pulps and open apices

When the pulp of a tooth is irreversibly inflamed or necrotic and the apex is open, conventional root canal treatment is difficult to perform and the outcome is uncertain. Traditionally, the apexification procedure has consisted of multiple and long‐term applications of calcium hydroxide [Ca(OH)2] to create an apical barrier to aid the obturation. Recently, artificial apical barriers such as those made with mineral trioxide aggregate (MTA) have been used in teeth with necrotic pulps and open apices. More recently, procedures referred to as regenerative endodontics have received much attention as an option for these teeth. The purpose of this article is to provide a comprehensive literature review from May 1952–May 2011 regarding the management of teeth with necrotic pulps and open apices. This review covers the articles published in dental journals and book chapters regarding the definition, history, materials used, animal and human studies, mechanisms of action, prognosis, as well as advantages and disadvantages of apexification, apical plugs, and regenerative endodontics.

Management of teeth with vital pulps and open apices

One of the main functions of the dental pulp is the formation of dentin. When the pulp undergoes pathological changes before complete root development, normal root growth is disrupted. If the pulp is reversibly inflamed due to caries or exposure, the treatment of choice is to maintain pulp vitality by pulp capping or pulpotomy. If the pulp is irreversibly inflamed or necrotic, traditional apexification procedures consist of multiple and long‐term applications of calcium hydroxide in order to create an apical barrier that aids in root canal obturation. Recently, artificial apical barriers using mineral trioxide aggregate (MTA) have been introduced. In addition, pulp regeneration (revascularization) has received attention as an option for such teeth. That topic will be addressed in the next chapter. In this review, we will give a brief description of the embryology of root development, major causes of pulpal inflammation, factors affecting treatment planning, and tests for diagnosing pulpal conditions. This will be followed by a comprehensive literature review from 1908 through June 2010 regarding the definition, history, materials used, animal and human studies, mechanisms of action, prognosis, as well as advantages and disadvantages of apexogenesis by pulp capping and pulpotomy.

The effects of short‐term calcium hydroxide application on the strength of dentine

Studies have suggested that the long-term exposure of dentin from immature teeth to calcium hydroxide may weaken the dentin but the effects of short-term exposure of dentin from mature teeth have not been reported. The aim of this study was to evaluate the effects of a short term application of calcium hydroxide on the strength of dentine from mature human permanent teeth. 50 human extracted single rooted disease-free permanent mandibular premolars were chosen. The root canals were prepared with rotary instruments and randomly assigned to two groups. In one group, the root canals were filled with a calcium hydroxide paste. Canals of teeth in the control group were left empty. All teeth were stored in normal saline for 30 days and then coronal third root dentin cylinders were created by removing the crown and apical portions of the teeth. An Instron machine was used to measure the compressive forces needed to break the dentin cylinders and data were analysed using the Student's t-test. The mean compressive force in the calcium hydroxide-filled teeth was significantly lower than that in the control teeth (210.6 +/- 32.3 kg cm(-1) vs 246.2 +/- 29.0 kg cm(-1) respectively, P < 0.001). Teeth subjected to 30 days application of calcium hydroxide required less compressive force to break root dentin cylinders. Further studies are necessary to determine whether similar effects would result if impact tests were performed.

Long Term Effect Of Calcium Hydroxide On The Microhardness Of Human Radicular Dentin – A Pilot Study”

Aim: The objective of this study was to evaluate the long term effect of calcium hydroxide-glycerin combination on the microhardness of human radicular dentin. Materials and methodology: One hundred and fifty freshly extracted single rooted human premolars were used in this study. All the teeth were decoronated at the cemento-enamel junction and the root canals were instrumented with protaper rotary files. The teeth were then randomly divided into three groups with 50 teeth in each group, where group I and II had teeth with calcium hydroxide application for 30 and 90 days respectively and group III had teeth with saline application for 90 days. The teeth in all the groups were sectioned longitudinally into two equal slabs and then subjected to Vickers microhardness testing.Statistical analysis: Statistical analysis was performed with the aid of SPSS v 12.0 software and the data were analyzed using One-Way ANOVA and Tukey’s HSD test. Results: There was a significant reduction (p<0.001) in the hardness values of specimens in Group-II (44.53 HV) as compared to Group-I – 57.87 HV and Group-III – 68.91 HV. Conclusion: The reduction in hardness can be attributed to the prolonged application of Calcium hydroxide, which can have a detrimental effect on the teeth making it more vulnerable to fracture.

An Evaluation of the Effect of Non-Setting Calcium Hydroxide on Human Dentine: A pilot Study

To evaluate the effect of non-setting calcium hydroxide (NSCH) on the hardness and elastic modulus of dentine from extracted permanent premolar human teeth. 30 freshly extracted single rooted human premolar teeth were decoronated and the roots then sectioned longitudinally into equal halves. In the experimental group a thin layer of NSCH was applied whilst the control group had no medicament. After 1, 3 and 6 months, nanoindentation was used to assess dentine hardness and the modulus of elasticity. Scanning Electron Microscopy (SEM) was used to visualize the depth of penetration of NSCH into the dentinal tubules. SEM images showed that there were no structural changes in the dentine slabs that had NSCH application after 1, 3 or even 6 months. However, penetration of NSCH into the dentine tubules was seen at both 3 and 6 months with a significant reduction in the hardness of dentine observed at 3 (p<0.02) and 6 months (p<0.01). The modulus of elasticity was significantly lower (p<0.01) at 6 months. It appears that there is a significant reduction in the hardness of dentine with increasing periods of calcium hydroxide application. Prolonged application of NSCH could have a detrimental effect on dentine, making the dentine more prone to fracture.

Change of oxalate form in pot‐grown napiergrass (Pennisetum purpureum Schumach) by application of calcium hydroxide

AbstractOxalate interferes with the absorption of calcium (Ca) in livestock. However, insoluble oxalate, which presents mostly as a complex combined with Ca, is not considered to be a problem in ruminants. The objective of this study was to test the possibility of increasing insoluble oxalate content in plants by increasing Ca supply in pot‐grown napiergrass (Pennisetum purpureum Schumach). The plants were cut three times at approximately 2‐month intervals from summer to autumn. Four treatments (0, 30, 60 and 90 g m−2) of Ca(OH)2 were applied in three equal split doses: before transplanting and soon after the first two cuttings. At almost all of the cuttings, soluble oxalate in forage showed a decreasing trend and insoluble oxalate and Ca concentration showed a reverse trend with an increased rate of Ca(OH)2 application. Averaged over the three cuttings, the 90‐g Ca(OH)2 treatment was most effective in reducing soluble oxalate by increasing insoluble oxalate, with significant (P &lt; 0.05) differences between the 0‐ and 90‐g Ca(OH)2 treatments. However, total oxalate content was not affected (P &gt; 0.05) by the rate of Ca(OH)2 application. Moreover, Ca(OH)2 application did not affect dry matter yield and the concentrations of magnesium, potassium and sodium of plant material. It may be concluded that the level of soluble oxalate in plants can be partially replaced by formation of insoluble oxalate using Ca(OH)2 fertilizer.

Bone repair using mineral trioxide aggregate combined to a material carrier, associated or not with calcium hydroxide in bone defects

Mineral trioxide aggregate (MTA) is a powder aggregate containing mineral oxides with a good biological action and may facilitate the regeneration of the periodontal ligament and formation of bone. Calcium hydroxide demonstrates antibacterial properties, enhances tissue dissolution, and induces bone formation. The objective of this study was to evaluate the MTA in the bone healing process and verify if the calcium hydroxide P.A. can improve and accelerate this process. It was used forty male Wistar rats, which were divided into two groups, considering or not the use of calcium hydroxide P.A. solution before treatment. Thus, each one of these groups was divided in four groups with five animals each, according to the treatment and the defect filled by: animal's coagulum, monoolein gel, MTA in aqueous solution, and MTA combined with monoolein gel. After 10 days, the animals were perfused and the right hemimandibles removed for histological analysis. Statistical analysis of the data showed significant difference between all analyzed groups when it was made comparisons using or not calcium hydroxide P.A. ( p < 0.0001). There was found statistical difference between the groups that was inserted or not MTA, independently the calcium hydroxide application ( p < 0.05). Results showed that the MTA used was able to induce bone regeneration and had its action optimized when combined to calcium hydroxide P.A.

Histological evaluation of odontoblast-like cells response after capping application of calcium hydroxide and hydroxilapatite in dog’s pulp

This study was conducted to observe the response of dog's dental pulp to hydrpxylapatite (Hap) and calcium hydroxide when used as pulp capping materials. After the pulps of 22 teeth were exposed, they were capped with either Hap or calcium hydroxide. Histological analysis was performed 8 weeks after treatment. Results showed that pulp exposure caused irreversible injury of odontoblasts, which were subsequently replaced by similar, odontoblast-like cells. These cells were able for reparative dentin bridge formation in 6 cases treated with calcium hydroxide and almost all the cases treated with hydroxylapatite. The presence of odontoblast-like cells seemed to be crucial for reparative dentinogenesis. The capping material was of less importance. In conclusion neither calcium hydroxide nor hydrxylapatite had completely satisfied all the requirements of an ideal capping material, although Hap can be recognized as a superior alternative to calcium hydroxide.

Root resorption associated with an impacted mesiodens: a surgical and endodontic approach to treatment

This article describes a case of root resorption of a maxillary non-vital immature incisor associated with an impacted and angulated mesiodens. The impacted tooth was surgically removed and the compromised incisor was subsequently endodontically treated. Over a period of 27 months the tooth was medicated with repeated applications of calcium hydroxide. Radiographically after 18 months, an incomplete hard tissue barrier was observed with full apical closure at the conclusion of 27 months of treatment. Once the patient was comfortable after surgical removal of the mesiodens, the tooth was asymptomatic and remained so for the duration of the treatment and after definitive restorative work had been completed.

Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs

This study aimed at evaluating the antisepsis of the root canal system (RCS) and periapical region (PR) provided by rotary instrumentation associated with chlorhexidine + calcium hydroxide as intracanal medicament. Chronic periapical lesions were induced in 26 pre-molar roots in two dogs. After microbiological sampling, automatic instrumentation using the Profile system and irrigation with 5.25% sodium hypochlorite solution, with a final rinse of 14.3% EDTA followed by profuse irrigation with physiological saline were carried out in 18 root canals. After drying the canals, a paste based on calcium hydroxide associated with a 2% chlorhexidine digluconate solution was placed inside them. After 21 days, the medication was removed, leaving the root canals empty and coronally sealed. After 96 hours, a final microbiological sample was obtained, followed by histomicrobiological processing by the Brown & Brenn method. Eight untreated root canals represented the control group (C-G). Based on the Mann-Whitney test at a confidence level of 5% (p < 0.05), the procedures of antisepsis used offered significant efficacy (p < 0.05) resulting in 100.0% of the canals free of microorganisms. In the C-G, an elevated incidence of various microbial morphotypes was confirmed in all sites of the RCS, with the presence of microbial colonies in the periapical region. In contrast, the experimental group showed a similar pattern of infection in the RCS, although less intense and a reduced level of periapical infection (p < 0.05). It was concluded that adequate instrumentation followed by the application of calcium hydroxide + chlorhexidine offered significant elimination of microorganisms.

ADJUNCTIVE INFRARED DIODE LASER THERAPY ACCELERATES HEALING IN APICAL GRANULOMAS: A CASE REPORT STUDY

The final stage of severe infection round the apex of a tooth is granuloma formation, the treatment of which can be a major problem in clinical dentistry. Although granulomas in the early stages can respond to conservative conventional therapy, such as the application of calcium hydroxide, many in the later stage require surgical intervention with the risk of postoperative sequelae and patient downtime. Low reactive-level laser therapy (LLLT) has been shown to reduce inflammation and accelerate wound healing. The present study was designed to assess the role of 830 nm diode laser therapy in conjunction with conservative conventional therapy in the treatment of severe apical granulomas. Thirty-three young male patients with severe apical granulomas participated in the study, 19 of whom were treated with conventional treatments, and 14 with calcium hydroxide combined with 0.5 J/cm2 - 2 J/cm2 intra- and extraoral diode laser therapy. Significant improvements were seen in the LLLT combination group compared with the control group in the time taken for the resolution of acute postoperative pain (100 vs 500 min) and inflammation (1.6 vs 5.6 days), and long-term tooth remineralization and alveolar bone regeneration (15 vs 33 months). LLLT with the 830 nm diode laser was shown to be safe and effective in combination with conservative conventional therapy in the treatment of severe apical granulomas and was superior to the conventional approach on its own for granulomas of similar severity.

Clinical application of calcium hydroxide in dental pathology and endodontics

Calcium hydroxide has a hard tissue inducing effect. It is a powder, that can be mixed with a physiological saline to a paste. The paste is highly alkaline with a pH 12.5 and its application to the pulp results in necrosis of the part of coronal pulp tissue shows no or only a milled inflammatory reaction. Analyzing the pH and the concentration of calcium ions in the periapical area, it is obvious that at least 2 weeks are necessary for calcium hydroxide bactericide activity. Calcium hydroxide retains its anti-bacterial properties for about two months when placed under a restoration, after which it degrades to calcium oxide and other less effective calcium salts. All calcium hydroxide preparations have a limited shelf life as they eventually turn into calcium oxide. Calcium hydroxide can be used as linings, for indirect and direct pulp cupping, root dressing, root canal sealant, apical closure. The vehicles play a supportive role, giving pastes chemical characteristics such as dissociation and diffusion as well as favoring the correct filling of the root canal which are decisive factors for antimicrobial potential and tissue healing. The mechanism of action of calcium hydroxide on tissues, inducing the deposition of mineralized tissue, is an extremely important aspect for the indication of calcium hydroxide, because it demonstrates biological compatibility of calcium hydroxide.

Endodontic treatment with application of Er:YAG laser waveguide radiation disinfection.

The objective of this study is to examine the ability of Er:YAG laser radiation. Using a movable waveguide helps to obtain an antibacterial effect, not only in root canal walls but also in the surrounding tissues. Conventional endodontic treatment is not fully effective due to microbial colonization of root canal walls dentin in premolars and molars. Various laser systems seem to be effective to kill the remaining microbial content in the root canal. The problem is in the flexibility of laser system tips. The Er:YAG laser system was designed with a fluorocarbon polymer-coated silver hollow glass waveguide. Root canal systems of 44 premolars and molars were treated endodontically, using a step-back technique; 10 teeth were then treated with calcium hydroxide paste, and 22 teeth were irradiated by a movable waveguide. Before and after treatment, the colony-forming units were counted to determine 21 various microorganisms. Classical enlargement and shaping of the root canal is effective in 60%. Application of calcium hydroxide prepares sterile root canal in 80%. Er:YAG laser irradiation via movable waveguide (energy of 100 mJ, 30 pulses, repetition rate 4 Hz) can ensure residual disinfection of the root canal. Application of Er:YAG laser radiation through a flexible waveguide helps to attain antibacterial effect, not only in the root canal walls, but also in the surrounding tissues. Therapeutic doses of laser radiation guarantee one-step disinfection, including of anaerobic microorganisms.

Immunohistochemical study of dental pulp applied with 4-META/MMA-TBB adhesive resin after pulpotomy

The purpose of this study was to investigate nerve regeneration and proliferative activity in amputated pulp tissue after the application of 4-META/MMA-TBB adhesive resin (4-META resin). Calcium hydroxide was used as a control material. At 3 days, fibroblast-like cells were positive for proliferating cell nuclear antigen (PCNA) in both 4-META resin- and calcium hydroxide-treated groups and were located mainly within 0.5 mm from the cut surface. Only a few fragmented neurofilament protein (NFP)-positive nerve fibers were observed in this area. At 7 and 14 days, the number of PCNA-positive cells had gradually decreased and regenerated NFP-positive nerve fibers were observed close to the cut surface of the pulp in both groups. At 21 days in the experimental group, several PCNA-positive cells were still found in the area 0.5 mm from the cut surface, and NFP-positive nerve fibers were detected about 0.15–;0.2 mm from the cut surface. In contrast, a dentin bridge was produced under the necrotic layer at 21 days in the control group. PCNA-positive cells were not found underneath the dentin bridge, but NFP-positive nerve fibers had regenerated close to it. These results suggest that although cell differentiation and nerve regeneration are delayed, wound healing occurred even after the application of 4-META resin to exposed pulp surface the same as calcium hydroxide application. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 51, 241–248, 2000

Immunohistochemical study of dental pulp applied with 4-META/MMA-TBB adhesive resin after pulpotomy

The purpose of this study was to investigate nerve regeneration and proliferative activity in amputated pulp tissue after the application of 4-META/MMA-TBB adhesive resin (4-META resin). Calcium hydroxide was used as a control material. At 3 days, fibroblast-like cells were positive for proliferating cell nuclear antigen (PCNA) in both 4-META resin- and calcium hydroxide-treated groups and were located mainly within 0.5 mm from the cut surface. Only a few fragmented neurofilament protein (NFP)-positive nerve fibers were observed in this area. At 7 and 14 days, the number of PCNA-positive cells had gradually decreased and regenerated NFP-positive nerve fibers were observed close to the cut surface of the pulp in both groups. At 21 days in the experimental group, several PCNA-positive cells were still found in the area 0.5 mm from the cut surface, and NFP-positive nerve fibers were detected about 0.15-;0.2 mm from the cut surface. In contrast, a dentin bridge was produced under the necrotic layer at 21 days in the control group. PCNA-positive cells were not found underneath the dentin bridge, but NFP-positive nerve fibers had regenerated close to it. These results suggest that although cell differentiation and nerve regeneration are delayed, wound healing occurred even after the application of 4-META resin to exposed pulp surface the same as calcium hydroxide application.

Recombinant human osteogenic protein-1 induces dentin formation: An experimental study in miniature swine

It was the aim of the present study to investigate the induction of dentin formation by recombinant human osteogenic protein-1 (hOP-1). In 4 adult miniature pigs a total of 16 teeth with artificially exposed dental pulps were capped with 3 mg of a complex of recombinant hOP-1 in collagen matrix (2.5 micrograms/mg), collagen matrix alone, or calcium hydroxide paste. Teeth were removed in block section after a healing period of 5 weeks. Decalcified sections were processed for light microscopy and histomorphometric analysis. In hOP-1 treated teeth substantial amounts of hard tissue formation (osteodentin and tubular dentin) had consistently led to a complete bridging of the defects. Less dentin formation was seen after calcium hydroxide application. In control defects collagen matrix alone failed to form complete dentin bridges. Recombinant human osteogenic protein-1 in a collagen carrier matrix appeared to be suitable as a bio-active capping agent for surgically exposed dental pulps.

The effects of copper and calcium foliar sprays on cherry and apple fruit quality

The effects of post-bloom applications of calcium hydroxide (3000 g per 100 1) either alone or mixed with copper hydroxide (150 g Kocide ®, 50% Cu per 100 1) on fruit quality of sweet cherry and apple were studied. The sprays were applied to sweet cherry trees within 6 weeks of flowering and to apple trees within 8 weeks of flowering. Calcium hydroxide alone had no effect on the quality parameters measured except that russet was decreased on ‘Golden Delicious’. Application of copper plus calcium mixture to ‘Bing’ and ‘Van’ cherries improved fruit resistance to cracking and firmness. This spray mixture also improved the flesh firmness of ‘Golden Delicious’ apples.

Influence of pH and calcium on growth and attachment of human fibroblasts in vitro.

Human embryonic diploid lung fibroblasts (HEDL fibroblasts) and periodontal ligament fibroblasts (PDL fibroblasts) were cultured in media at fixed pH levels ranging between 7.2 and 8.4 and fixed calcium concentrations ranging between < or = 100 microM and 20 mM in an attempt to mimic the effects of calcium hydroxide on vital cell functions such as attachment and growth. PDL fibroblasts appeared to be more susceptible to changes in pH and calcium concentration than HEDL fibroblasts. At pH levels above 7.8, both attachment and growth decreased significantly. Growth was influenced more by changes in pH and calcium concentration than was attachment. The results help explain why intracanal application of calcium hydroxide through its high pH may impair periodontal healing in areas on the root surface where the cementum has been damaged by either trauma or periodontal treatment, thus allowing the medicament access to the root surface.