Interferon-gamma inducible protein 16 and type I interferon receptors expression in experimental apical periodontitis induced in wild-type mice.

AIM: The aim of this study was to evaluate the IFI16 and IFN-α/ß receptors expression during the genesis and development of experimental apical periodontitis (AP) in mice teeth. METHODOLOGY: Apical periodontitis was induced in the lower first molars of 40 C57BL/6 mice. They were divided according to the experimental periods 2, 7, 14, 21 and 42 days (n = 8 per group). Five animals were used as a control group (without AP). Specimens were submitted to histological processing for description of the inflammatory process, immunostaining for the presence/absence and localization of IFI16 and IFN-α/ß receptors (qualitative and semi-quantitative analysis) and tartrate-resistant acid phosphatase (TRAP) histoenzimology. RESULTS: The results showed a gradual development of AP over the experimental times. The expression of IFI16 was noticeably more exacerbated in the experimental early period (day 2) whilst the lowest expression was observed in the control group (p = .02). For IFN-α/ß receptors, a higher intensity staining was observed 42 days after AP induction, that was statistically different from the control group (p = .02). In addition, the number of TRAP-positive cells was higher on the later periods (days 21 and 42; p < .001). CONCLUSION: IFI16 protein expression was highest during the early periods after AP induction in mice teeth, whilst IFN-α/ß receptor expression was highest after AP became established.

Radiotherapy Activates Matrix Metalloproteinases in the Dentinoenamel Junction of Primary Teeth.

Purpose: Radiation-related caries is characterized by enamel delamination near the dentinoenamel junction (DEJ). We investigated the activity and expression of the matrix metalloproteinases (MMPs) -2 and -9 in order to understand disease pathogenesis in teeth submitted or not to radiotherapy (RT).
Methods: In situ zymography and immunofluorescence assays were performed to evaluate the activity and expression of MMPs -2 and -9, respectively. Twelve primary second molars were randomly assigned into two experimental subgroups: irradiated and nonirradiated. Dental fragments were exposed to radiation at a dose fraction of two Gy for five consecutive days until reaching the total dose of 60 Gy. The percentage of fluorescence in the DEJ was evaluated in three distinct regions of the tooth (cervical, cusp, and pit). The regions were photographed under fluorescence microscopy at 1.25× and 5× magnification.
Results: The intensity of fluorescence per mm 2 in the DEJ was higher in the cervical region of irradiated primary teeth (P <0.05) versus nonirradiated ones. In these areas, immunofluorescence revealed expression of MMPs -2 and -9.
Conclusion: Radiotherapy can increase the activity of MMPs -2 and -9 in the cervical region of the DEJ of primary teeth.

Efficiency of different storage media for avulsed teeth in animal models: a systematic review.

BACKGROUND/AIMS: Tooth avulsion consists of the complete displacement of a tooth from the alveolar socket. When immediate replantation is not possible, the avulsed tooth should be kept in a storage medium capable of maintaining the viability of periodontal ligament (PDL) cells on the root surface. However, there is no consensus on the best storage medium able to prevent sequels such as ankylosis and tooth resorption. The aim of this study was to perform a systematic review to evaluate the in vivo effectiveness of different storage media for avulsed teeth. METHODS: Two reviewers performed a database search for studies published between January 1950 and December 2015 which were indexed in the PubMed, Scopus, Web of Science, and Bireme databases. An additional manual search was performed. Studies with animal models that evaluated tooth avulsion, storage media, and replantation were included. After full-text analysis of the potentially relevant studies, the selected studies were included in the systematic review. RESULTS: The database search found 157 distinct studies evaluating avulsed teeth storage media. However, only six studies met the selection criteria and were included in the review. There was a high variability in the study estimates for the parameters analyzed. When assessing the quality and level of evidence of each study, one study was rated as having a very low level of evidence, four studies had low levels of evidence, and one had a moderate level of evidence. CONCLUSION: As a result of data heterogeneity and limitations of the studies, there was insufficient evidence to determine the most effective storage medium for avulsed teeth.

Antibacterial Effect of Calcium Hydroxide With or Without Chlorhexidine as Intracanal Dressing in Primary Teeth With Apical Periodontitis.

PURPOSE: The purpose of this study was to evaluate in vivo the antibacterial effect of calcium hydroxide (CH) dressings, with or without chlorhexidine (CHX), on human primary teeth with apical periodontitis. METHODS: Forty root canals in 40 children were selected. A first microbiological sample was obtained after coronal opening, and the teeth were randomly assigned to Group 1 (root canals filled with CH paste) and Group 2 (CH paste plus 1.0 percent CHX). After 30 days, the dressing was removed and the canals were allowed to remain empty for 72 hours. Subsequently, the second microbiological sample was collected. After performing microbiological tests, the data were subjected to statistical analysis to compare the two CH dressings regarding reducing the absolute levels of microorganisms and with respect to total microbial elimination. All analyses were performed with a significance level of five percent. RESULTS: Both CH dressings provided a significant reduction in the number of microorganisms (anaerobic, aerobic, black-pigmented bacilli, streptococci and Streptococcus mutans) in a similar way (P>0.05). However, in terms of complete elimination of microbiota, CH paste alone exhibited greater efficacy (P<0.05). CONCLUSIONS: The addition of chlorhexidine did not provide additional antimicrobial benefits compared with pure calcium hydroxide paste as an intracanal dressing in primary teeth with apical periodontitis.

Physicochemical Properties of Root Canal Filling Materials for Primary Teeth.

This study evaluated physiochemical proprieties of a calcium hydroxide-based paste (Calen®) combined with a zinc oxide cement at different ratios (1:0.5, 1:0.65, 1:0.8 and 1:1). Materials were compared regarding setting time, pH variation, radiopacity, solubility, dimensional changes, flow and release of chemical elements. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Longer setting time and higher dimensional changes and solubility values were exhibited by 1:0.65 and 1:0.5 ratios (p<0.05). The 1:0.5 and 1:0.65 ratios exhibited the highest pH values at all time points. All materials exhibited high radiopacity values. Significant differences were found only between 1:0.5 and 1:1 ratios for calcium and zinc release (p<0.05), whereas the amount of zirconium was similar among all groups (p>0.05). Considering the evaluated proprieties, combinations of Calen® paste with ZO at 1:0.5 and 1:0.65 ratios had the best results as root canal filling materials for use in primary teeth.

Physicochemical Properties of Root Canal Filling Materials for Primary Teeth

Abstract This study evaluated physiochemical proprieties of a calcium hydroxide-based paste (Calen(r)) combined with a zinc oxide cement at different ratios (1:0.5, 1:0.65, 1:0.8 and 1:1). Materials were compared regarding setting time, pH variation, radiopacity, solubility, dimensional changes, flow and release of chemical elements. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Longer setting time and higher dimensional changes and solubility values were exhibited by 1:0.65 and 1:0.5 ratios (p<0.05). The 1:0.5 and 1:0.65 ratios exhibited the highest pH values at all time points. All materials exhibited high radiopacity values. Significant differences were found only between 1:0.5 and 1:1 ratios for calcium and zinc release (p<0.05), whereas the amount of zirconium was similar among all groups (p>0.05). Considering the evaluated proprieties, combinations of Calen(r) paste with ZO at 1:0.5 and 1:0.65 ratios had the best results as root canal filling materials for use in primary teeth.

Resumo O objetivo do presente estudo foi avaliar propriedades físico-químicas da pasta à base de hidróxido de cálcio (Calen(r)) combinado com diferentes proporções de óxido de zinco (OZ) (1:0,5 e 1:0,65, 1:0,8 e 1:1) (Calen(r) /OZ). Os materiais foram comparados quanto ao tempo de endurecimento, variação do pH, radiopacidade, solubilidade, alterações dimensionais, escoamento e liberação de elementos químicos. Os dados obtidos foram submetidos à análise de variância (nível de 5% de significância). Maior grau de endurecimento, valores de alterações dimensionais, e solubilidade foram encontrados para Calen(r) /OZ 1:0,65 e 1:0,5. Calen(r) /OZ 1:0,5 e 1:0,65, apresentaram os maiores valores de pH em todos os momentos. Todos os materiais apresentaram valores elevados de radiopacidade com diferenças significativas (p>.05). Foram encontradas diferenças significativas apenas entre Calen(r) /OZ de 1:0,5 e 1:1 na liberação de cálcio e zinco (p< 0,05), enquanto que a quantidade de zircônia foi semelhante entre todos os grupos analisados (p>.05). Em relação às propriedades avaliadas no presente estudo, as combinações de Calen(r) com óxido de zinco nas proporções 1:0,5 e 1:0,65 são mais adequadas como material obturador para os canais radiculares de dentes decíduos.

Stepwise Excavation Allows Apexogenesis in Permanent Molars with Deep Carious Lesions and Incomplete Root Formation.

This study evaluated the stepwise excavation technique in 138 permanent molars with deep carious lesions and incomplete root formation within a 24-month clinical and radiographic follow-up period. In 96.7% of the cases, success was observed (no pain, integrity of restoration margins, absence of radiographic alterations and apexogenesis). The cases of failure (3.3%) were due to the loss of the temporary restoration. In conclusion, the stepwise excavation is a promising technique for permanent teeth with deep carious lesions and incomplete root formation as a minimally invasive approach because it allows the preservation of pulp vitality and occurrence of apexogenesis.

Resin luting materials: Tissue response in dog's teeth.

The aim of this study was to evaluate radiographically and histologically the pulpal and periapical response to self-adhesive (Rely X™ Unicem) and self-etching and self-curing (Multilink(®)) resin-based luting materials in deep cavities in dogs' teeth. Deep class V cavities (0.5-mm-thick dentin) were prepared in 60 canine premolars and the following materials were applied on cavity floor: Groups I/V-RelyX™ Unicem; Groups II/VI-Multilink(®); Groups III/VII-zinc phosphate cement (control) and; Groups IV/VIII-gutta-percha (control). Cavities were restored with silver amalgam. Animals were euthanized after 10 days (groups I-IV) and 90 days (groups V-VIII). Tooth/bone blocks were radiographed and processed for histopathological evaluation of pulp and periapical tissue response to the materials. All materials presented similar histopathological features and radiographic findings at both periods. The pulp tissue was intact. The apical and periapical regions and periodontal ligament thickness were normal. No inflammatory cells, resorption of mineralized tissue (dentin, cementum, and alveolar bone) or bacteria were observed. The lamina dura was intact and no areas of periapical bone rarefaction or internal/external root resorption were observed radiographically. It can be concluded that Rely X™ Unicem and Multilink(®) caused no adverse tissue reactions and may be indicated for cementation of indirect restorations in deep dentin cavities without pulp exposure.

Physicochemical properties and interfacial adaptation of root canal sealers.

This study compared the physicochemical properties and interfacial adaptation to canal walls of Endo-CPM-Sealer, Sealapex and Activ GP with the well-established AH Plus sealer. The following analyses were performed: radiopacity, pH variation and solubility using samples of each material and scanning electron microscopy of root-filled bovine incisors to evaluate the interfacial adaptation. Data were analyzed by the parametric and no-parametric tests (α=0.05). All materials were in accordance with the ANSI/ADA requirements for radiopacity. Endo-CPM-Sealer presented the lowest radiopacity values and AH Plus was the most radiopaque sealer (p=0.0001). Except for ActiV GP, which was acidic, all other sealers had basic chemical nature and released hydroxyl ions. Regarding solubility, all materials met the ANSI/ADA recommendations, with no statistically significant difference between the sealers (p=0.0834). AH Plus presented the best adaptation to canal walls in the middle (p=0.0023) and apical (p=0.0012) thirds, while the sealers Activ GP and Endo-CPM-Sealer had poor adaptation to the canal walls. All sealers, except for ActiV GP, were alkaline and all of them fulfilled the ANSI/ADA requirements for radiopacity and solubility. Regarding the interfacial adaptation, AH Plus was superior to the others considering the adaptation to the bovine root canal walls.

Physicochemical Properties and Interfacial Adaptation of Root Canal Sealers

This study compared the physicochemical properties and interfacial adaptation to canal walls of Endo-CPM-Sealer, Sealapex and Activ GP with the well-established AH Plus sealer. The following analyses were performed: radiopacity, pH variation and solubility using samples of each material and scanning electron microscopy of root-filled bovine incisors to evaluate the interfacial adaptation. Data were analyzed by the parametric and no-parametric tests (α=0.05). All materials were in accordance with the ANSI/ADA requirements for radiopacity. Endo-CPM-Sealer presented the lowest radiopacity values and AH Plus was the most radiopaque sealer (p=0.0001). Except for ActiV GP, which was acidic, all other sealers had basic chemical nature and released hydroxyl ions. Regarding solubility, all materials met the ANSI/ADA recommendations, with no statistically significant difference between the sealers (p=0.0834). AH Plus presented the best adaptation to canal walls in the middle (p=0.0023) and apical (p=0.0012) thirds, while the sealers Activ GP and Endo-CPM-Sealer had poor adaptation to the canal walls. All sealers, except for ActiV GP, were alkaline and all of them fulfilled the ANSI/ADA requirements for radiopacity and solubility. Regarding the interfacial adaptation, AH Plus was superior to the others considering the adaptation to the bovine root canal walls.

Este estudo comparou as propriedades físico-químicas e a adaptação interfacial às paredes do canal dos cimentos Endo-CPM-Sealer, Sealapex e Activ GP com o bem estabelecido cimento AH Plus. As seguintes análises foram realizadas: radiopacidade, variação de pH e de solubilidade utilizando amostras de cada material, e microscopia eletrônica de varredura utilizando incisivos bovinos obturados para avaliar a adaptação interfacial. Os dados foram analisados utilizando testes paramétricos e não-paramétricos (α=0,05). Todos os materiais estavam de acordo com os requerimentos da ANSI/ADA para radiopacidade, sendo que o Endo-CPM-Sealer apresentou os menores valores de radiopacidade e o AH Plus foi o cimento mais radiopaco (p=0,0001). Exceto o Activ GP, que foi ácido, todos os outros cimentos apresentaram natureza química básica e liberaram íons hidroxila. Com relação à solubilidade, todos os materiais estavam de acordo com as recomendações da ANSI /ADA, sem diferença significante entre os cimentos (p=0,0834). O AH Plus apresentou a melhor adaptação às paredes do canal nos terços médio (p=0,0023) e apical (p=0,0012), enquanto que os cimentos Activ GP e Endo-CPM-Sealer apresentaram uma pobre adaptação às paredes do canal. Em conclusão, todos os cimentos, exceto o Activ GP, foram alcalinos e todos preencheram os requerimentos da ANSI/ADA para radiopacidade e solubilidade. Com relação à adaptação interfacial, o AH Plus foi superior aos demais para adaptação às paredes do canal radicular de incisivos bovinos.

Filtek™ Silorane and Filtek™ Supreme XT resins: tissue reaction after subcutaneous implantation in isogenic mice.

The aim of this study was to evaluate the tissue compatibility of a silorane-based resin system (Filtek™ Silorane) and a methacrylate-based nanoparticle resin (Filtek™ Supreme XT) after implantation in the subcutaneous connective tissue of isogenic mice. One hundred and thirty five male isogenic BALB/c mice were randomly assigned to 12 experimental and 3 control groups, according to the implanted material and the experimental period of 7, 21 and 63 days. At the end of each period, the animals were killed and the tubes with the surrounding tissues were removed and processed for microscopic analysis. Samples were subjected to a descriptive and a semi-quantitative analyses using a 4-point scoring system (0-3) to evaluate the collagen fiber formation and inflammatory infiltrate. Data were statistically analyzed using the Kruskal Wallis test (α=0.05). The results showed that there was no significant difference between the experimental and control groups considering the three evaluation periods (p>0.05). The silorane-based and the methacrylate-based nanoparticle resins presented similar tissue response to that of the empty tube (control group) after subcutaneous implantation in isogenic mice.

FiltekTM Silorane and FiltekTM Supreme XT resins: tissue reaction after subcutaneous implantation in isogenic mice

The aim of this study was to evaluate the tissue compatibility of a silorane-based resin system (FiltekTM Silorane) and a methacrylate-based nanoparticle resin (FiltekTM Supreme XT) after implantation in the subcutaneous connective tissue of isogenic mice. One hundred and thirty five male isogenic BALB/c mice were randomly assigned to 12 experimental and 3 control groups, according to the implanted material and the experimental period of 7, 21 and 63 days. At the end of each period, the animals were killed and the tubes with the surrounding tissues were removed and processed for microscopic analysis. Samples were subjected to a descriptive and a semi-quantitative analyses using a 4-point scoring system (0-3) to evaluate the collagen fiber formation and inflammatory infiltrate. Data were statistically analyzed using the Kruskal Wallis test (?=0.05). The results showed that there was no significant difference between the experimental and control groups considering the three evaluation periods (p>0.05). The silorane-based and the methacrylate-based nanoparticle resins presented similar tissue response to that of the empty tube (control group) after subcutaneous implantation in isogenic mice.

O objetivo do presente estudo foi avaliar a compatibilidade tecidual de um sistema resinoso à base de silorane (FiltekTM Silorane) e de uma resina nanoparticulada à base de metacrilato (FiltekTM Supreme XT), após implantação no tecido conjuntivo subcutâneo de camundongos isogênicos. Um total de 135 camundongos isogênicos BALB/c machos foram randomicamente divididos em 12 grupos experimentais e em 3 grupos controles, de acordo com o material implantado e com o período experimental (7, 21 e 63 dias). Ao final de cada período, os animais foram mortos, sendo os tubos removidos com o tecido circundante e processados para análise microscópica. As lâminas foram submetidas a análise descritiva e análise semi-quantitativa empregando um sistema de escores de 4 pontos (0-3), a fim de avaliar a formação de fibras colágenas e o infiltrado inflamatório. Os dados obtidos foram submetidos à análise estatística por meio do teste de Kruskal Wallis (?=0,05). Os resultados mostraram que não houve diferença estatisticamente significante entre os grupos experimentais e controles, considerando os três períodos de avaliação (p>0,05). As resinas à base de silorane e à base de metacrilato apresentaram resposta tecidual semelhante à do tubo vazio (controle), após implantação no tecido conjuntivo de camundongos isogênicos.

Large apical periodontitis healing following root canal dressing with calcium hydroxide: a case report / Reparo de lesão periapical extensa após utilização de curativo de demora à base de hidróxido de cálcio: relato de caso

PURPOSE: The objective of this paper is to report the clinical case of a patient who presented a chronic apical periodontitis, arising from internal inflammatory resorption followed by pulp necrosis, and a long-term success of a root canal therapy using calcium hydroxide as root canal dressing. CASE DESCRIPTION: A 20-year-old male patient presented for routine dental treatment. By radiographic examination we noted an extensive radioluscent area, laterally to the permanent maxillary right lateral incisor, with possibility of communication with the lateral periodontium, suggestive of a chronic apical periodontitis. Due to external root resorption detection, we used a calcium hydroxide root canal dressing, changed every 15 days, for a period of 2 months. Root canal filling was performed using gutta-percha cones by lateral condensation technique Radiographic follow up held after 19 years of treatment indicated a periodontium in conditions of normality, with the presence of lamina dura. CONCLUSION: Calcium hydroxide is a suitable material to be used as root canal dressing in teeth with apical periodontitis. Long-term evaluation demonstrated the satisfactory clinical outcome following root canal treatment.

OBJETIVO: O objetivo deste trabalho é relatar o caso clínico de um paciente que apresentava lesão periapical crônica decorrente de necrose de pulpar e o sucesso a longo prazo de uma terapia endodôntica utilizando o hidróxido de cálcio como curativo de demora. DESCRIÇÃO DO CASO: O paciente, do gênero masculino, com 20 anos de idade, compareceu à Clínica Odontológica para tratamento de rotina. Por meio de exames radiográficos observamos uma área radioluscente extensa, lateralmente ao incisivo lateral superior direito, com possibilidade de comunicação com o periodonto lateral, sugestivo de lesão periapical. Devido à presença de reabsorção radicular externa, foi utilizado um curativo de demora à base de hidróxido de cálcio (Calen®), trocado a cada 15 dias, por um período de 2 meses. A obturação do canal radicular foi realizada com cones de guta-percha pela técnica de condensação lateral ativa. O acompanhamento radiográfico realizado após 19 anos do tratamento endodôntico indicou um periodonto em condições de normalidade, com integridade da lamina dura. CONCLUSÃO: O hidróxido de cálcio é um material adequado para ser usado como curativo de demora em dentes com lesão periapical, uma vez que a avaliação a longo prazo demonstrou resultados clínicos satisfatórios após o tratamento endodôntico.

Direct pulp capping with a self-etching adhesive system: histopathologic evaluation in dogs' teeth.

OBJECTIVE: This study evaluated histopathologically the response of pulp and periradicular tissues after pulp capping with an all-in-one self-etching adhesive system in dogs' teeth. STUDY DESIGN: Forty teeth of 4 dogs were assigned to 3 groups according to the pulp capping material: G1 (n = 20): self-etching adhesive system; G2 (n = 10): Ca(OH)(2); G3 (n = 10): zinc oxide-eugenol. The animals were killed 7 and 70 days after pulp capping. The pieces containing the pulp-capped teeth were removed and processed for histologic analysis. RESULTS: At 7 days, no dentin bridge formation was observed; G1 and G3 exhibited inflammatory pulpal alterations, whereas G2 presented only mild inflammatory infiltrate in the pulp tissue adjacent to the capping material, the remainder being intact. At 70 days, no specimen in G1 or G3 presented dentin bridge formation. The remaining pulp tissue exhibited severe inflammatory alterations and areas of necrosis. In G2, all specimens showed dentin bridge formation and absence of inflammation and mineralized tissue resorption. No bacteria were identified using Brown and Brenn staining techniques in all 3 groups at any observation period. CONCLUSION: According to the conditions of this study, direct pulp capping with the self-etching adhesive system did not allow pulp tissue repair and failed histopathologically in 100% of the cases.

Aggressive periodontitis associated with Papillon-Lefèvre syndrome: report of a 14-year follow-up.

This case report describes the periodontal management, therapeutic approach, and 14-year follow-up of a patient diagnosed with Papillon-Lefevre syndrome (PLS). A female child, diagnosed with PLS-associated periodontitis at the age of 9 years and 11 months, presented with hyperkeratosis of the palms and soles, as well as generalized aggressive periodontitis. The dental treatment comprised standard periodontal debridement, scaling and root planing, instructions on oral hygiene, restorations, extraction of hopelessly affected teeth and a therapeutic use of antibiotics. The concomitant supportive periodontal therapy and antibiotic coverage could not stop the loss of periodontal attachment and destruction of the alveolar bone. Four years after treatment was initiated, the last remaining teeth were extracted and complete dentures were constructed. The dentures have been periodically replaced and the patient continues to return for follow-up once a year. The combination of intensive periodontal treatment and antibiotic regimen only temporarily delayed periodontal disease progression and did not prevent loss of both primary and permanent teeth. The outcome of this long-term follow-up case report shows that management of PLS-associated periodontitis is further complicated when the patient is first seen in the mixed dentition stage or later. In these situations, the chances of controlling the progression of periodontal breakdown and minimizing tooth loss are greatly reduced.

Effect of a calcium hydroxide-based root canal dressing on periapical repair in dogs: a histological study.

OBJECTIVE: To compare the periapical repair of teeth with periapical lesion following root canal treatment by using a calcium hydroxide-based intracanal dressing for several time periods or filling in a single visit. STUDY DESIGN: After induction of periapical lesions in 4 dogs, the root canals were prepared using 5.25% sodium hypochlorite for irrigation, and animals were separated into 4 experimental groups; in group I, root canals were filled in a single session; in groups II, III, and IV, a calcium hydroxide-based dressing was kept in place for 15, 30, or 180 days, respectively. Root canals from groups I, II, and III were filled with gutta-percha cones and AH Plus sealer. After 180 days, animals were killed and histological sections were stained with hematoxylin-eosin to evaluate periapical repair. RESULTS: Periapical repair was better in groups II, III, and IV (intracanal dressing) compared with group I (single session; P < .05). CONCLUSION: The use of a calcium hydroxide-based intracanal dressing was important for periapical repair in teeth with periapical lesion. Dressing with calcium hydroxide paste results in better periapical repair than when the root canal is filled in a single-session treatment.

Evaluation of periapical repair following retrograde filling with different root-end filling materials in dog teeth with periapical lesions.

OBJECTIVE: The objective of this study was to evaluate periapical repair following retrograde filling using different root-end filling materials. STUDY DESIGN: After induction of periapical lesions, 48 root canals from dog teeth were partially filled. Endodontic surgery was performed and 3 different materials were used for root-end filling: Sealer 26, Sealapex plus zinc oxide, or mineral trioxide aggregate (MTA). No additional procedures were performed in the control group after partial filling of the root canal. After 180 days, the animals were killed, the maxillas and mandibles were removed, and specimens were submitted for histologic processing. RESULTS: Histopathologic analysis revealed similar periapical repair for the groups in which Sealer 26, Sealapex plus zinc oxide, and MTA were used (P > .05). The control group showed unsatisfactory periapical repair (P < .05). CONCLUSION: There was no difference in periapical tissue healing after retrograde filling with the tested materials, which indicates that these 3 root-end filling materials are equally useful.

Effect of rotary or manual instrumentation, with or without a calcium hydroxide/1% chlorhexidine intracanal dressing, on the healing of experimentally induced chronic periapical lesions.

OBJECTIVE: To evaluate the healing of experimentally induced chronic periapical lesions in dogs at 30, 75, and 120 days after root canal instrumentation with rotary NiTi files or manual K-files, with or without a calcium hydroxide/1% chlorhexidine paste intracanal dressing. STUDY DESIGN: The second, third, and fourth mandibular premolars and the second and third maxillary premolars of 5 dogs (12 to 18 months of age, weighing 8 to 15 kg) were selected for treatment (a total of 82 root canals). After pulp removal, the root canals were left exposed to the oral cavity for 7 days to allow microbial contamination, after which the root canals were sealed with ZOE cement until periapical lesions were confirmed with radiography. Group I and II teeth were instrumented with manual K-files using the crown-down technique. In group III and IV teeth, NiTi rotary files were used. The apical delta was perforated by using #20 to #30 K-files at the length of the tooth, thus creating a standardized apical opening. The apical stop was enlarged to size 70, with 2.5% sodium hypochlorite irrigation at each file change. Teeth in groups II and IV were dressed with calcium hydroxide (Ca(OH) 2 )/1% chlorhexidine (CHX) paste for 15 days before root filling. Group I and III teeth did not receive an intracanal dressing. The access openings of the teeth were permanently restored with silver amalgam condensed on a glass ionomer cement base. Pairs of standardized periapical radiographs were taken at the beginning of the treatment (0 days) and at 30, 75, and 120 days after filling. RESULTS: There was no significant difference in the rate of radiographic healing of the periapical lesions between manual and rotary instrumentation. Radiographs taken at 120 days showed that the treatment with Ca(OH) 2 /1% CHX paste resulted in a significant reduction in mean size of the periapical lesions in comparison to single-session treatment. These findings were also true for histologic observations. CONCLUSION: The findings support the hypothesis that, regardless of the instrumentation technique (manual or rotary), the use of an intracanal dressing is important in the endodontic treatment of dog's teeth with experimentally induced chronic periapical lesions.

Comparison of rotary and manual instrumentation techniques on cleaning capacity and instrumentation time in deciduous molars.

PURPOSE: The aim of this study was to evaluate, in vitro, the cleaning capacity and time needed for instrumentation of root canals of deciduous molars by manual and rotary instrumentation. METHODS: Thirty-three deciduous molar root canals were injected with India ink and divided into 3 groups: group I--the root canal instrumented manually with K files; group II--the root canal instrumented with rotary Profile .04 instruments; group III--control group, (ie, root canals not instrumented). Instrumentation time was recorded. The teeth were cleared and the removal of India ink was measured in the cervical, middle, and apical thirds. RESULTS: There was no significant difference for cleaning capacity between manual and rotary techniques in the 3 root thirds (P>.05), but both techniques were different from the control group (P<.001). Significantly less time was needed for instrumentation with the rotary technique (3.46 minutes) than with the manual technique (9.06 minutes). CONCLUSIONS: Although no differences were found for cleaning capacity, the reduction of instrumentation time by the rotary technique was a relevant clinical factor for endodontic treatment.

EM evaluation of bacterial biofilm and microorganisms on the apical external root surface of human teeth.

The aim of this study was to evaluate the presence of bacterial biofilm on the external surface of the root apex in teeth with pulp necrosis, with and without radiographically visible periapical lesions, and in teeth with a vital pulp. Twenty-one teeth were extracted, eight with pulp necrosis and periapical lesions, eight with pulp necrosis without radiographically visible periapical lesions, and five with a vital pulp. The roots were sectioned, and the root apexes (+/- 3 mm) were processed for scanning electron microscope evaluation. The surface of the apical root was evaluated for the presence of microorganisms, root resorption, and biofilm. There were no microorganisms on the apical root surface of either teeth with pulp vitality or with pulp necrosis with no radiographically visible periapical lesions. Microorganisms were always present in teeth with pulp necrosis and radiographically visible periapical lesions. These included cocci, bacilli, and filaments and the presence of an apical biofilm. Apical biofilm is clinically important because microbial biofilms are inherently resistant to antimicrobial agents and cannot be removed by biomechanical preparation alone. This may cause failure of endodontic treatment as a consequence of persistent infection.