氢氧化钙-ZOE糊剂用于乳牙根管治疗术的疗效

目的：观察氢氧化钙-ZOE糊剂作为乳牙根管充填材料的疗效。方法：用3种根管充填材料对223个乳磨牙进行根管充填治疗，试验组用氢氧化钙-ZOE糊剂根管充填（A组），对照组用氢氧化钙糊剂（B组）和ZOE糊剂（C组）根管充填，观察6个月后的疗效。结果：A、B、C3组的成功率分别为90．2％、88％和71．1％。A、B两组的疗效相似（x^2检验，P〉0．05），A与C、B与C两组之间有明显差异（P〈0．05）。结论：氢氧化钙-ZOE糊剂用于乳牙根管充填的临床疗效比较理想，是一种可选择的乳牙根充材料。     

Calcium hydroxide as a root canal filling material in primary teeth--a pilot study

A pilot study was carried out in five mandibular primary molars using calcium hydroxide (Ca(OH)2) Paste as root canal filling material to find out an alternative to the routinely used zinc oxide eugenol (ZnOE), which is non-resorbable and causes deflection of succedaneous teeth. The six month clinical and radiographic follow-up carried out at 2 months interval, revealed that the treated teeth with Ca(OH)2 as root canal filling material were successful, showing no pain and tenderness to percussion. A tendency for decrease in size of radiolucency was seen. Two teeth showed complete healing of the periradicular radiolucency. Depletion of Ca(OH)2 paste was seen from the root canals even prior to physiological resorption of roots in 2 out of 5 treated teeth.     

Effect of unintentionally extruded calcium hydroxide paste including barium sulfate as a radiopaquing agent in treatment of teeth with periapical lesions: report of a case

Calcium hydroxide [Ca(OH)2] has been widely used as short- or long-term intracanal antibacterial dressing material after endodontic treatment. In general when used in endodontics, Ca(OH)2 paste is composed of the powder, a vehicle, and a radiopacifier. To provide radiopacity, barium sulfate (BaSO4) powder is usually added to the paste. In this case report, BaSO4:Ca(OH)2 powders (ratio 1:8) and distilled water were mixed and applied as dressing material after root canals of mandibular left canine and premolar teeth with periapical lesions. However, the prepared paste was unintentionally extruded into the periapical lesion during application. The patient was seen 12 and 36 months later, at which point periapical healing was evaluated. At this time, it was observed that the periapical lesion had disappeared, but white radiopaque spots were seen at the place where calcium hydroxide remnants had originally been present. The presented case report reveals that when Ca(OH)2 paste that included BaSO4 was applied as an intracanal dressing and extruded through the periapical lesion associated with pulpless teeth, it had no detrimental effect. However, healing might take longer when Ca(OH)2 paste including BaSO4 is used, so deliberate overextension is not advocated.     

Hydroxyl and calcium ions diffusion from endodontic materials through roots of primary teeth - in vitro study

The purpose of this research was to evaluate the diffusion of calcium (Ca+2) and hydroxyl (OH-) ions from materials with a calcium hydroxide base - Ca(OH)2 through the intact roots of deciduous teeth. This diffusion of ions is important for periapical healing. Forty-six deciduous teeth were selected and instrumented to their working length with #40 files. The teeth were washed during cleaning and shaping with a 1% sodium hypochlorite (NaOCl) solution. The canals were dried with paper points. The teeth were divided into 4 groups based on the sealer type, with 10 specimens in each group. A fifth group of 6 teeth without sealer constituted the control group. The materials used as sealers were: Ca(OH)2 paste associated to propylene glycol (CaPE) thickened at the proportion of 2:1 w/v; UFSC (Federal University of Santa Catarina) paste - a mixture of 0.3g of zinc oxide with 0.3g of Ca(OH)2 with 0.2ml of olive oil 1:1 w/w; Vitapex? and Sealapex?. The coronal access was sealed with a glass ionomer after the root had been filled with each sealer. A one-third apical surface and foramen was hard-pressed with Araldite?. The teeth were stored individually in flasks containing saline solution at 37oC and 100% humidity. The OH- and Ca+2 ions diffusion levels were determined using a pH meter and an atomic absorption spectrometer. Data were collected at 48 hours and at intervals of 7, 30, 45 and 60 days. Statistical analysis was performed using ANOVA to compare groups. In the pH evaluation, the CaPE group presented the largest OH- ions diffusion, which peaked at sixty days (p=0.0309), when compared to the other groups (p<0.0001). In relation to amount of Ca+2 ions released, the CaPE paste showed the best results, followed by the UFSC's paste. These results suggest that the CaPE paste was the material that allowed the highest diffusion of OH- and Ca+2 ions.     

Literature survey of apexification in connection with three cases

Endodontic treatment of three non-vital immature teeth is discussed. According Moorrees et al. root formation was in the stage two, six and four respectively. After access to the root canal, removing necrotic pulp and effective chemo-mechanical cleansing, Ca(OH)2 paste was used as a temporary filling material in each case. In two cases after closing the apical opening, permanent obturation was performed with half heated gutta-percha and lateral condensation to obtain a good seal. In one case permanent filling of the canal occurred with gutta-percha and AH26 as a sealer. In the first case two years, in the second case five years after obturation of the root canal with gutta-percha, periapical healing was evident in the control radiograph. In the third case using gutta-percha with AH26 as a sealer after two years new periapical lesion has developed. On the bases of literature data and our experiences in the case of non-vital immature teeth. Ca(OH)2 paste is the best temporary filling material to induce apexification process, and the half heated gutta-percha obturation is the most suitable permanent root filling material.     

Effect of calcium hydroxide-based materials on periapical tissue healing and orthodontic root resorption of endodontically treated teeth in dogs

Abstract – This study evaluated periapical tissue healing and orthodontic root resorption of endodontically treated teeth sealed with calcium hydroxide in dogs. The sample consisted of three contralateral pairs of maxillary incisors and two contralateral pairs of mandibular incisors in each of two dogs using a split mouth design. After biomechanical preparation of the teeth in the first group (n = 10), a Ca(OH)₂ dressing was placed for 14 days before root canal filling with Ca(OH)₂‐based sealer (Sealapex) and gutta‐percha points. In the second group (n = 10), root canals were obturated immediately after the mechanical preparation with gutta‐percha points and zinc oxide and eugenol (ZOE)‐based sealer (Endofill). After completion of endodontic treatment, the teeth were moved with an orthodontic appliance with a calibrated force of 200 g, reactivated every 21 days. After 105 days, the animals were killed and the teeth were removed upon completion of active treatment, without a period of recovery, and prepared for histomorphological analysis. All sections of each tooth were graded subjectively on a scale from one to four to obtain the average of the 16 histomorphological parameters analysed. Evaluation of the differences between the two treatment protocols was made with Mann–Whitney U‐test. It was observed that the teeth treated with Ca(OH)₂‐based materials provided better outcomes (P = 5%), with complete repair of all root resorption areas, high rate of biological closure of the main canal and apical accessory canals by newly formed cementum, less intense and extensive chronic inflammatory infiltrate, and better organization of the periodontal ligament. Under the tested conditions, Ca(OH)₂‐based materials had a favourable action on periapical tissue healing and repair of orthodontic root resorption in endodontically treated dogs’ teeth.     

氢氧化钙糊剂用于乳牙根管充填的疗效观察

目的 :观察氢氧化钙碘仿糊剂作为乳牙根管充填材料的临床疗效。方法 :用两种根管充填材料对乳磨牙进行根管充填 ,实验组用氢氧化钙碘仿糊剂根管充填 ,对照组用氧化锌碘仿糊剂根管充填 ,观察一年后的疗效。结果 :实验组平均有效率为 84.1% ,对照组有效率为 81.4% ,实验组与对照组无显著差异(P >0 .0 5 )。结论 :氢氧化钙碘仿糊剂用于乳牙根管充填的疗效比较理想。     

A SEM investigation of accessory foramina in the furcation areas of primary molars

The purpose of this study was to determine the prevalence and anatomic characteristics of accessory foramina in the external and internal furcation areas of primary molars. Sixty human primary molars were divided into two equal groups. The teeth of the experimental group showed in previous radiographic examination the presence of a radiolucency area confined to the inter-radicular region, while the teeth of the control group had no sign of pulpal inflammation in the clinical and/or radiographic examination. The specimens were observed by scanning electron microscope (SEM). The external furcation area (EFA) showed a higher prevalence of accessory foramina than the internal furcation area (IFA) (P<0.05). However, the comparison between the two groups did not show statistically significant difference (P>0.05). The presence of accessory canals should not be considered the only reason for inter-radicular pathological bone resorption following pulpal necrosis in deciduous molars.     

Management of wide open apices in non-vital permanent teeth with Ca(OH)2 paste

A retrospective study on 15 non-vital immature incisor teeth was done using Ca(OH)2 Pulpdent paste. A success rate of 100 percent was achieved within one year. The variables influencing the time taken for apexification were also evaluated. The teeth were followed up to a period of 24 months. It was found that older children having narrow open apex had a shorter treatment time than the younger children (NS); teeth without periapical infection showed some amount of root growth and closing of apex that was faster than those with periapical infection (p < 0.001). The calcified bridge formed following apexification is a porous structure. This investigation provides information about the time taken and procedure required to achieve apical barrier formation in non-vital immature incisors.     

Massive extrusion of calcium hydroxide paste containing barium sulphate during endodontic treatment

A 31‐year‐old woman was referred for the evaluation of persistent lower lip numbness following endodontic treatment of tooth #36. Imaging examinations showed a large amount of radiopaque/hyperdense material spread in an angiographic distribution in the left mandibular body region. Laboratory analyses of tooth #36 and adjacent periapical tissue, surgically extracted in an external Service due to acute pain following endodontic treatment, identified chronic inflammatory reaction and birefringent crystalloid foreign bodies rich in barium and sulphur, leading to the diagnosis of alveolar nerve injury due to accidental extrusion of intracanal dressing material composed of calcium hydroxide [Ca(OH)₂] paste incorporated with barium sulphate. Clinicians should be aware that Ca(OH)₂ when in contact with periapical tissues may lead to persistent toxicities, such as necrosis, pain and paraesthesia. Therefore, injectable Ca(OH)₂ systems should be used with caution because they can cause paste extrusion and damage to the lower alveolar nerve.     

Effects of local irritation and dextran sulphate administration on the periodontium of the rat

Local irritation, provided by means of silk ligatures at the necks of mandibular first molars of rats, caused significant resorption of crestal alveolar bone. This resorption did not change significantly in extent from 27 days after placement of the ligatures. However, in rats receiving injections of dextran sulphate, there was no significant reduction in height of crestal alveolar bone of non-ligated mandibular first molars. The injections of dextran sulphate caused the appearance of large numbers of multinucleated osteoclasts adjacent to the alveolar bone surrounding the mandibular molar teeth. There was increased irregularity of the periodontal surface of this alveolar bone. When the local and general factors were combined there was a significant increase in resorption of the crestal alveolar bone mesial to the mandibular first molars at 37 days after placement of ligatures. The systemic agent was seen to augment the effects of the local irritant beyond the time at which local irritation alone ceased to have any demonstrable effect.     

Orthodontically induced root and alveolar bone resorption: inhibitory effect of systemic doxycycline administration in rats

The aim of the present study was to investigate the effect of systemic administration of low-dose doxycycline (DC) on orthodontic root resorption. The effect on alveolar bone, the cell population involved, and the amount of tooth movement were also evaluated.Fifty-six 40-50-day-old male Wistar rats were used. Six animals served as untreated controls. Six animals were only administered DC for 7 days, by means of a mini-osmotic pump implanted subcutaneously. In 44 animals the maxillary first molar was mesialized by a fixed orthodontic appliance exerting 50 g force upon insertion. In 28 of these animals DC was administered at the time of appliance insertion and throughout the experiment. The animals were sacrificed 7, 10 or 14 days after force application and block sections processed for analysis. An area including the mesial aspect of the distopalatal root and the adjacent inter-radicular alveolar bone was histomorphometrically evaluated. The root resorption area, absolute alveolar bone area, distance between first and second molars, number of odontoclasts, osteoclasts, mononuclear cells on the root, tartrate-resistant acid phosphatase (TRAP)-positive cells on the root, bone, and in the periodontal ligament (PDL) were compared between DC-treated and non-DC-treated animals.The results revealed a significant reduction in root resorption, the number of odontoclasts, osteoclasts, mononuclear cells on the root surface, and TRAP-positive cells on the root and bone for the DC-administered group. The absolute alveolar bone area was greater, whereas the distance between the first and second molars did not differ between groups. In conclusion, systemic administration of low-dose DC in rats may have an inhibitory effect on orthodontically induced resorptive activity.     

Evaluation of various root canal filling materials in primary molar pulpectomies: an in vivo study

PURPOSE: To evaluate the clinical and radiographic success of zinc oxide-eugenol (ZOE), Calcicur, Sealapex and Vitapex in primary molar pulpectomies. METHODS: 80 primary molars, showing signs of pulpal and/or periapical involvement, with no abnormal mobility, were selected from 76 children aged between 4-9 years-old, free from systemic disease. Radiographic evaluation was done to exclude teeth showing internal or pathological external root resorption and/or inadequate bone support. The selected teeth (20 in each group) were randomly treated with ZOE, Sealapex, Calcicur and Vitapex. The procedure involved primarily a one-visit pulpectomy. The teeth were evaluated clinically and radiographically every 2 months for a period of 18 months. RESULTS: In the ZOE group, all pulpectomies were successful. In the Sealapex group, two pulpectomies and in the Calcicur group, four pulpectomies showed complete resorption of the material in the root canal. Although re-treatment was performed, those teeth had to be removed due to pathological root resorption. In the Vitapex group, although six pulpectomies showed resorption of the filling material within the canals, this had no effect on the clinical and radiographical success of the treatment.     

Histological and histochemical quantification of root resorption incident to the application of intrusive force to rat molars

This study was conducted to investigate the nature of root resorption resulting from intrusive forces applied to the rat lower molars, by means of histological and histochemical techniques with tartrate resistant acid phosphatase (TRAP). Thirty-eight 13-week-old Wistar strain male rats were used. Intrusive force was created by a fixed appliance which was adjusted to exert an initial force of 50 g for the duration of 1, 2, and 3 weeks. The degree of root resorption and distribution of TRAP positive cells were evaluated. On the root surface, the TRAP positive scores were low in the apical regions. Significant differences in the scores were found in the inter-radicular region of the roots between the experimental and control groups for the 2- and 3-week groups. More active resorption of bone occurred during the experimental period, as denoted by greater TRAP positive scores on the bone than on the root surface. Root resorption scores in the apical root region were larger in the 2- and 3-week groups than in the 1-week group. Significant differences in the root resorption scores were also found between the 1- and 3-week groups in the inter-radicular region, indicating that intrusive force application of a longer duration may lead to a higher frequency of root resorption. It is shown that, irrespective of the level of TRAP positive cells and root resorption scores, the degree of root resorption activity is higher in the apical root region than in the inter-radicular area. These results indicate that cellular cementum may be resorbed more easily because of its richer organic components and low mineralized structure.     

犬乳恒牙替换期间活化T细胞核因子NFATc1表达的研究

目的通过观察犬乳恒牙替换过程中活化T细胞核因子（nuclear factor of active T cells,NFAT）NFATc1的表达探讨其在此过程中的作用及意义。方法制备犬乳恒牙替换各阶段乳牙根、牙槽骨、恒牙胚的组织标本切片,用免疫组织化学方法检测NFATc1在犬乳恒牙替换期间的表达。结果NFATcl在破骨细胞、恒牙胚成釉细胞、成牙本质细胞层中表达阳性。结论NFATc1可能参与了犬乳恒牙替换生理过程中乳牙根、牙槽骨的吸收和恒牙胚的发育。     

Changes in periodontal membrane, bone and permanent teeth following experimental pulpal injury in deciduous molar teeth of monkeys (Macaca irus)

Experimental pulpal exposures were successfully completed in 38 deciduous molar teeth of young monkeys (M. irus) which were left open to the mouth for periods varying from 45 to 212 days with a mean of 101.5 days. Total pulpal necrosis was noted in each case which led to histological changes in the tissues around one or more of the root apices in all teeth. Inter-radicular changes were seen histologically in only 24 of the 38 exposed molars i.e. 63 per cent. Of the teeth showing tissue changes in the bone of the inter-radicular region, 58 per cent showed radiographically detectable changes in that area. Only 26 per cent of the teeth showing histologically detectable apical bone destruction gave evidence of this radiographically. Whilst inflammatory cell spread to the follicular tissues of underlying permanent teeth occurred in 21 per cent of exposed molars, only 10 per cent showed either evidence of degenerative changes in the dental epithelium or enamel hypoplasia of the developing tooth. The inter-radicular tissue changes did not appear to be due to the passage of bacteria or their products through the dentinal tubules leading to the bifurcation or trifurcation of the roots.     

Indirect pulp treatment: in vivo outcomes of an adhesive resin system vs calcium hydroxide for protection of the dentin-pulp complex

PURPOSE: The purpose of this prospective and randomized in vivo study was to compare the clinical and radiographic outcomes of an adhesive resin system vs a calcium hydroxide liner for protection of the dentin-pulp complex of primary molars treated with indirect pulp treatment. METHODS: Forty-eight primary molars with deep occlusal caries, but without preoperative signs and symptoms of irreversible pulpitis, received indirect pulp treatment and were restored with a composite resin (Z100). The teeth were randomly divided into 2 groups according to the material used for protection of the dentin-pulp complex: (1) adhesive resin system (Scotchbond MultiPurpose); and (2) calcium hydroxide liner (Dycal). These teeth were evaluated clinically and radiographicaly for 2 years. RESULTS: After 2 years, 83% (19/23) of the teeth treated with calcium hydroxide and 96% (24/25) of teeth treated with only the adhesive resin system presented a successful outcome, as determined by clinical and radiographic examination. Interradicular and/or periapical lesions were the most predominant signs of treatment failure, since 3 out of 23 teeth treated with calcium hydroxide and 1 out of 25 teeth treated with only adhesive resin presented this outcome. One tooth treated with the calcium hydroxide liner was diagnosed with internal root resorption at the 18-month examination. Of the 5 teeth diagnosed from radiographs as a failure of the indirect pulp treatment, none presented clinical signs/symptoms of pulpitis or necrosis such as the presence of fistula, enhanced tooth mobility, or pain. CONCLUSIONS: This study demonstrates that protection of the dentin-pulp complex of primary molars with an adhesive resin system results in similar clinical and radiographic 2-year outcomes as compared to calcium hydroxide when indirect pulp treatment is performed in Class I composite restorations.     

Pulpotomy of deciduous teeth

Rather easy to perform, pulpotomy of the deciduous teeth is the most frequent endodontic treatment performed on children, but also the most controversial. Based on the amputation of the pulp chamber and the conservation of the inflammation-free root canals, the clinical results can be good, depending on the materials used. In this, calcium hydroxide (Ca(OH)2) as well as zinc-oxide-eugenol (ZOE) have been proven very inflammatory whereas Formocresol (FC) remains the reference even if its clinical toxicity is still reported in literature on a very controversial way. Nevertheless, this was sufficient to trigger and stimulate a search for alternatives, and led to the proposition to use ferric sulfate and even more recently MTA as new bases for the treatment of the pulp stumps after pulp chamber amputation.     

The role of endodontics in the treatment of luxated permanent teeth

Abstract  – Pulp necrosis is a common complication following traumatic dental injuries and is related to the type and severity of the injury, as well as to the stage of development of the injured tooth. Endodontic intervention is required when there are clinical and radiographic signs of pulpal infection and its sequelae. Arrested tooth development with periradicular pathosis, external inflammatory root resorption, sinus tract formation and pain on percussion are indicative of root-canal infection in the post-traumatized teeth, and require immediate endodontic treatment. The use of calcium hydroxide in the treatment of teeth with post-traumatic pulp necrosis and its sequelae has been shown to be extremely beneficial for the long-term retention of the injured teeth. Calcium hydroxide has been shown to arrest and repair external inflammatory root resorptive defects, eliminate the endodontopathic microorganisms from the root canal system and induce hard-tissue barrier formation at the apex of non-vital immature teeth. This paper reviews the endodontic treatment required by post-traumatic non-vital permanent teeth.     

Eighteen‐month clinical and radiographic evaluation of two root canal‐filling materials in primary teeth with pulp necrosis secondary to trauma

Abstract – Aim: This study compared clinically and radiographically the use of zinc oxide and eugenol cement (ZOE) and a commercial calcium hydroxide and polyethylene glycol‐based paste (Calen^®) thickened with zinc oxide as root canal‐filling materials for primary teeth with pulp necrosis secondary to trauma within 18 months of follow up. Material and methods: Eligible patients of both genders aged 2 years and 6 months to 5 years and 10 months who had been referred for dental treatment at a pediatric dental trauma service and presented at least one anterior primary tooth (central and/or lateral incisor) with pulp necrosis secondary to traumatic injury were selected. Twenty‐six children (n = 31 teeth) with mean age of 3.4 years met the inclusion criteria and were enrolled after parental written consent. The root canals were instrumented and filled with either ZOE (group I; n = 15 teeth) or Calen^® paste [composition: 2.5 g calcium hydroxide, 0.5 g zinc oxide, 0.05 g colophony, and 1.75 ml polyethylene glycol 400 (vehicle)] thickened with zinc oxide (Calen^®/ZO; group II; n = 16 teeth). ZO was added to the Calen^® paste for slowing paste resorption, which should ideally occur simultaneously with the physiologic resorption of primary tooth roots. Clinical success after 18 months of follow up was considered as absence of pain, tooth mobility or fistula, and radiographic success as the partial or total remission of apical periodontitis, absence of pathological root resorption or presence of new bone formation. Results: Eighteen months after treatment, the teeth obturated with ZOE and Calen^®/ZO presented statistically similar (Fisher’s exact test; P > 0.05) success rates of 93.3% and 87.5%, respectively. Conclusion: Our results showed the clinical and radiographic outcomes for Calen^®/ZO to be equal to those for ZOE after 18 months, suggesting that both materials can be indicated for obturating primary teeth with pulp necrosis after trauma.