Histological evaluation of experimentally induced subluxation in rat molars and its implications on the management of orthodontic treatment.

The purpose of this study was to evaluate the histological alterations occurred in the periradicular region of rat molars after intentional subluxation using an experimental method to induce dentoalveolar trauma. Eighteen adult male Wistar rats (Rattus norvegicus albinus) were selected for the study. The dentoalveolar trauma was experimentally induced by the application of an occlusogingival force on the occlusal surface of the maxillary right first molar using a tensiometer secured on a fully articulated support with adjustable steel shafts. The animals were assigned to six groups (n = 3), according to the intensity of the force applied to induce trauma: Group I (GI, control) - no force application; Groups II-VI (GII-GVI) - the animals were subjected to 600, 700, 800, 900 and 1000 cN force, respectively. After experimental induction of trauma, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. In the animals of GII, GIII and GIV, the histological alterations were similar to those described for GI. GVI (1000 cN) presented the most severe alterations, with the occurrence of buccal bone plate fracture, alveolar fracture and root fracture, which are not present in mild traumatic injuries like subluxation. The 900 cN force (GV) was capable to produce clinical and histological alterations in the gingival and periodontal tissues compatible with those observed in subluxation.

Sodium hypochlorite chemical burn. Case report.

Sodium hypochlorite (NaOCl) is a well documented and widely accepted intracanal irrigant used to disinfect the pulp space in endodontic therapy. NaOCl can be an extremely cytotoxic material; therefore, care must be taken with its use. The authors present a case of periradicular extravasation of NaOCl with sequelae of pain, swelling, ecchymosis and parasthesia consistent with a chemical burn. The patient was treated with a nonsurgical medical management approach. She experienced a complete resolution of signs and symptoms, aside from a persistent residual focal parasthesia.

Efectividad de la membrana de fibrina rica en plaquetas asociada al colgajo de reposición coronal / Effectiveness of the platelet-rich fibrin membrane associated to coronally repositioned flap

Introducción: El colgajo de reposición coronal constituye una técnica ventajosa para el tratamiento de la recesión periodontal. Cuando esa técnica es combinada con diferentes biomateriales los resultados son superiores desde el punto de vista de la cobertura radicular y la estabilidad en el tiempo. Objetivo: Evaluar la efectividad de la membrana de fibrina rica en plaquetas combinada con el colgajo de reposición coronal en la cobertura radicular. Métodos: Se realizó una investigación cuasiexperimental con pacientes atendidos en la consulta de Periodoncia de la Facultad de Estomatología de Villa Clara durante el periodo comprendido entre marzo del 2017 y mayo del 2019. La población de estudio estuvo constituida por 41 pacientes que presentaban recesión periodontal y requerían recubrimiento radicular mediante la técnica del colgajo de reposición coronal. Se empleó un muestreo no probabilístico intencional por criterios y la muestra quedó constituida por 26 pacientes que cumplieron los criterios establecidos para el estudio. Se establecieron sitios de estudio y sitios de control. Las variables estudiadas fueron: edad, sexo, extensión longitudinal de la recesión, cobertura radicular, clasificación de Miller, anchura y ganancia de la encía insertada, categorías de evaluación y efectividad del tratamiento. Resultados: En el 92,45 por ciento de los dientes ubicados en los sitios de estudio predominó la categoría de evaluación favorable. El porcentaje de efectividad del tratamiento fue superior en los sitios de estudio en un 33,96 por ciento con relación a los controles. Conclusiones: Se consideró más efectivo el tratamiento de la membrana de fibrina rica en plaquetas asociada al colgajo de reposición coronal(AU)

Introduction: Coronally repositioned flap constitutes an advanced technique for the treatment of periodontal recession. When combined with different biomaterials the results are much more encouraging regarding root coverage and stability in time. Objective: to assess the effectiveness of the platelet-rich fibrin membrane combined with coronal repositioned flap in the root coverage. Methods: A quasi-experimental research was carried out in patients treated at the periodontal office of the Dentistry faculty in Villa Clara province from March 2017 to May 2019. The population was constituted by 41 patients who suffered from periodontal recession and required root coverage using coronally repositioned flap. An intentional non-probabilistic sample was used resulting in 26 patients with the established criteria. Study and control sites were established. Variables such as age, sex, recession length, root coverage, Miller's classification, width and gaining of the attached gingiva, assessment categories and effectiveness of treatment were studied. Results: A favorable assessment category was predominant in 92,45 percent of teeth located in the study sites. The percentage of effectiveness of treatment was higher in the study sites in 33,96 percent in relation to the control sites . Conclusions: The treatment of the platelet-rich fibrin membrane associated with coronally repositioned flap was considered more effective(AU)

Responses of the pulp, periradicular and soft tissues following trauma to the permanent teeth.

Trauma to the permanent teeth involves not only the teeth but also the pulp, the periodontal ligament, alveolar bone, gingiva and other associated structures. There are many variations in the types of injuries with varying severity and often a tooth may sustain more than one injury at the same time. In more severe trauma cases, there are many different cellular systems of mineralized hard and unmineralized soft tissues involved, each with varying potential for healing. Furthermore, the responses of the different tissues may be interrelated and dependent on each other. Hence, healing subsequent to dental trauma has long been known to be very complex. Because of this complexity, tissue responses and the consequences following dental trauma have been confusing and puzzling for many clinicians. In this review, the tissue responses are described under the tissue compartments typically involved following dental trauma: the pulp, periradicular and associated soft tissues. The factors involved in the mechanisms of trauma are analysed for their effects on the tissue responses. A thorough understanding of the possible tissue responses is imperative for clinicians to overcome the confusion and manage dental trauma adequately and conservatively in order to minimize the consequences following trauma.

Effects of injury and inflammation on pulpal and periapical nerves.

Several studies dealing with the reactions of dental nerve fibers to injury and inflammation are reviewed in this article. The subgroup of dental nerve fibers that contains calcitonin gene-related peptide (CGRP) was examined by immunocytochemistry at various times (1 to 35 days) after one of three degrees of injury: (a) Mild: Four days after making shallow cavities into cervical dentin of first molars of anesthetized adult rats, we found that CGRP fibers had sprouted into the subjacent odontoblast layer and dentin, and then returned to normal by 3 wk. (b) Intermediate: If the cervical cavities were acid etched, we found damage to the odontoblast layer, microabscess formation, and sprouting of CGRP fibers near the abscess, with subsequent formation of reparative dentin and healing. (c) Severe: If the pulp was exposed, a variety of reactions could occur, the most prevalent of which was a severe necrosis leading to development of periapical lesions. Analysis of the progressive stages of pulpal abscess and necrosis showed sprouting CGRP nerve fibers (a) at the retreating interface between abscess and vital pulp; (b) in periapical areas during onset of lesions; and (c) around chronic abscesses in granulomatous periodontal tissues. These studies are discussed in relation to various dental clinical problems such as hypersensitive teeth, episodic toothache, early onset of periapical lesions, dental anesthesia, and possible roles for sensory fibers and neuropeptides in tissue defense and healing.

Micro-endodontic nonsurgical retreatment.

Clinicians frequently encounter endodontically treated teeth that are failing. The vast majority of these cases can be predictably retreated nonsurgically. Integration of specific technology, coupled with breakthrough techniques, are described and powerfully demonstrated. This article is designed for the dental team whose vision is to preserve strategic teeth and create endodontic excellence for its patients.

[The morphohistochemical shifts in the trigeminal ganglia of dogs with experimental traumatic periodontitis]. / Morfogistokhimicheskie sdvigi v troinichnykh uzlakh sobak pri éksperimental'nom travmaticheskom periodontite.

A model of traumatic periodontitis was created in 36 mongrel dogs and effects of periapical inflammation focus on trigeminal ganglia neurone structure were studied 1, 2, 3, 6, 12, and 24 months after experimental exposure of the animals. Histologic study was carried out by routine methods. In the first months after the intervention the morphologic shifts in the neurones represented drastic irritation and destruction. Later focal and diffuse inflammatory infiltrates and glial element growth were detectable in the ganglial stroma; reduced biopolymer levels were observed in the neurones and accumulation of their level in ganglial stroma. These data evidence an unfavorable effect of periapical focus on trigeminal ganglion elements.

Acidente com hipoclorito de sódio durante tratamento endodôntico: análise de prontuário / Accident injection with sodium hypochlorite during endodontic treatment: case report

O sucesso do tratamento endodôntico está diretamente ligado ao processo de limpeza e modelagem dos canais radiculares. E para se conseguir a limpeza e desinfecção são utilizadas substâncias químicas auxiliares como coadjuvantes ao preparo mecânico, pois são essenciais na redução de microrganismos presentes no sistema de canais radiculares. Dentre as principais substâncias químicas auxiliares empregadas, a que apresenta maior destaque é o Hipoclorito de Sódio. O objetivo do presente estudo é mostrar através de uma análise de prontuário, um relato de um acidente com hipoclorito de sódio durante um atendimento odontológico. Para isso, um prontuário foi selecionado, onde a paciente procurou a clínica do Curso de Odontologia do Centro Universitário da Serra Gaúcha para realizar tratamento endodôntico do dente 16. Durante este procedimento, ocorreu um extravasamento do hipoclorito de sódio aos tecidos periapicais, e partir deste fato foi possível relatar maneiras de como prevenir, tratar e evitar esse tipo situação(AU)

The success of endodontic treatment is directly related to the root canal cleaning and modeling process. In order to achieve cleaning and disinfection, auxiliary chemical substances are used as auxiliaries to the mechanical preparation, since they are essential in the reduction of microorganisms present in the root canal system. Among the main auxiliary chemical substances employed, the most prominent is Sodium Hypochlorite. The objective of the present study is to show through an analysis of medical records, an account of an accident with sodium hypochlorite during a dental care. For this, a chart was selected, where the patient sought the clinic of the Dentistry Course of the University Center of Serra Gaúcha to perform endodontic treatment of the tooth 16. During this procedure, an extravasation of the sodium hypochlorite occurred to the periapical tissues, and from this It was possible to report on ways to prevent, treat and avoid this type of situation(AU)

Effect of MTA-based sealer on the healing of periapical lesions.

UNLABELLED: Some manufacturers have recently added specific components to improve the ease of handling and insertion material properties of MTA in order to create MTA-based sealers. OBJECTIVE: The aim of this study was to evaluate the healing of periapical lesions in canine teeth after a single session of endodontic treatment with MTA Fillapex® compared with Sealapex® or Endo-CPM-Sealer®. MATERIAL AND METHODS: Sixty-two root canals were performed on two 1-year-old male dogs. After coronal access and pulp extirpation, the canals were exposed to the oral cavity for 6 months in order to induce periapical lesions. The root canals were prepared, irrigated with a solution of 2.5% sodium hypochlorite and filled with gutta-percha and different sealers, according to the following groups: 1) Sealapex®; 2) Endo-CPM-Sealer®; and 3) MTA Fillapex®. Some teeth with periapical lesions were left untreated for use as positive controls. Healthy teeth were used as negative controls. After 6 months, the animals were sacrificed and serial sections from the roots were prepared for histomorphologic analysis and stained with hematoxylin and eosin and the Brown and Brenn technique. The lesions were scored according to pre-established histomorphologic parameters and the scores statistically analyzed using the Kruskal-Wallis test. RESULTS: All 3 materials produced similar patterns of healing (p>0.05); in particular, persistent inflammation and absence of complete periapical tissue healing were consistently noted. CONCLUSIONS: Preparation of the infected root canals followed by filling with the materials studied was insufficient to provide complete healing of the periapical tissues.

Tissue damage after sodium hypochlorite extrusion during root canal treatment.

Sodium hypochlorite solution is toxic to vital tissues, causing severe effects if extruded during endodontic treatment. This paper presents a report on the tissue damage related to inadvertent extrusion of concentrated sodium hypochlorite solution during root canal treatment. A 65-year-old woman was referred with moderate pain, ecchymosis, and severe swelling of the right side of the face. These symptoms appeared immediately after a root canal treatment of the maxillary right canine, which had been started 21 hours earlier. It was diagnosed as air emphysema related to sodium hypochlorite solution extravasation during the endodontic treatment. To avoid this, an initial radiograph should be taken to determine the correct canal working length and confirm root canal integrity.

Effect of MTA-based sealer on the healing of periapical lesions

Some manufacturers have recently added specific components to improve the ease of handling and insertion material properties of MTA in order to create MTA-based sealers. Objective The aim of this study was to evaluate the healing of periapical lesions in canine teeth after a single session of endodontic treatment with MTA Fillapex® compared with Sealapex® or Endo-CPM-Sealer®. Material and Methods Sixty-two root canals were performed on two 1-year-old male dogs. After coronal access and pulp extirpation, the canals were exposed to the oral cavity for 6 months in order to induce periapical lesions. The root canals were prepared, irrigated with a solution of 2.5% sodium hypochlorite and filled with gutta-percha and different sealers, according to the following groups: 1) Sealapex®; 2) Endo-CPM-Sealer®; and 3) MTA Fillapex®. Some teeth with periapical lesions were left untreated for use as positive controls. Healthy teeth were used as negative controls. After 6 months, the animals were sacrificed and serial sections from the roots were prepared for histomorphologic analysis and stained with hematoxylin and eosin and the Brown and Brenn technique. The lesions were scored according to pre-established histomorphologic parameters and the scores statistically analyzed using the Kruskal-Wallis test. Results All 3 materials produced similar patterns of healing (p>0.05); in particular, persistent inflammation and absence of complete periapical tissue healing were consistently noted. Conclusions Preparation of the infected root canals followed by filling with the materials studied was insufficient to provide complete healing of the periapical tissues. .

Relação entre presença de fendas de cristais de colesterol em lesão periapical e nível de colesterol sérico / Relationship between the presence of clefts of cholesterol crystals in periapical lesion and serum cholesterol level

Introdução: Uma infecção crônica nos tecidos periapicais pode desencadear uma lesão periapical em função da estimulação e da proliferação dos restos epiteliais de Malassez. Ao estudo microscópico, é possível detectar a presença de fendas de cristais de colesterol no interior de cistos e granulomas. De acordo com alguns estudos, a origem do colesterol no interior de lesões no periápice pode ser, parcialmente, por causa da condensação e da cristalização de colesterol dentro da parede do cisto. Outros estudos afirmam que a presença de colesterol pode ser derivada de produtos metabólicos locais ou da circulação vascular. Objetivo: O presente estudo teve por objetivo analisar a relação entre as fendas de cristais de colesterol encontradas nas lesões periapicais e os níveis de colesterol sérico. Material e Método: Estudo observacional de natureza descritiva, que incluiu 70 pacientes portadores de lesões periapicais, de acordo com exame radiográfico, atendidos no Departamento de Odontologia da Universidade Federal de Sergipe. Esses pacientes foram submetidos à exodontia da unidade dentária acometida e à remoção da lesão periapical, sendo esta peça encaminhada para exame anatomopatológico. Na mesma consulta, era solicitado um lipidograma para avaliação das taxas de colesterol sérico dos pacientes. Resultado: Fendas de cristais de colesterol estavam presentes apenas em cistos grandes (maiores que 1,5 cm de diâmetro, aproximadamente) e, portanto, mais antigos. Conclusão: A presença de cristais de colesterol é rara nas lesões periapicais. O estudo sugere uma relação entre a presença dos cristais de colesterol e o índice de colesterol sérico elevado, em lesões grandes e antigas.

Introduction: A chronic infection in periapical tissue can trigger a periapical lesion due to stimulation and proliferation of epithelial rests of Malassez. On microscopic study, it is possible to detect the presence of clefts of cholesterol crystals within cysts and granulomas. According to some studies, the source of cholesterol inside the periapice lesions may be partially due to the condensation and crystallization of cholesterol in the cyst wall. Yet another part, can be derived metabolic products local or vascular circulation. Objective: This study aimed to analyze the relationship between the clefts of cholesterol crystals found in periapical lesions and cholesterol levels in the blood circulation. Material and Method: An observational study of a descriptive nature that included 70 patients with periapical lesions (according to radiographic examination) at the Department of Dentistry, Federal University of Sergipe. These patients underwent extraction of the affected tooth unit and removal of the periapical lesion, and this number sent for pathological examination. At the same query was asked a lipid profile to assess rates of serum cholesterol of patients. Result: Clefts of cholesterol crystals were present only in cysts (larger than 1.5 cm in diameter, approximately), and therefore older. Conclusion: The presence of cholesterol crystals is rare in periapical lesions. The study suggests a relationship between the presence of cholesterol crystals and the rate of cholesterol serum levels in large and old injuries.

Estudo longitudinal do sucesso clínico-radiográfico de dentes tratados com medicação intracanal de hidróxido de cálcio / Longitudinal study of clinical-radiographic success of teeth treated with calcium hydroxide intracanal dressing

Introdução: O tratamento endodôntico é de fundamental importância para abolir a infecção presente em dentes que apresentam necrose pulpar. Objetivo: O objetivo do presente estudo foi avaliar clínica e radiograficamente a eficácia dos tratamentos de canais radiculares de dentes com lesão periapical crônica, efetuados pelos graduandos em Odontologia, da Faculdade de Odontologia de Araçatuba - UNESP. Material e Método: Foram selecionados 100 pacientes que possuíam dentes com lesão periapical crônica para serem tratados. Após o preparo biomecânico, os canais radiculares receberam uma medicação intracanal de hidróxido de cálcio durante o período de 14 dias. Os canais radiculares foram obturados com cimento endodôntico à base de hidróxido de cálcio. Foi realizada a proservação por um período entre oito e 11 meses. Resultado: A análise dos resultados permitiu constatar a porcentagem de 78,46% dos casos com reparo total da lesão periapical e de 21,54% dos casos em que não houve evidências de reparo. Conclusão: Ocorreu reparo das lesões periapicais nos dentes tratados pelos graduandos da Faculdade de Odontologia de Araçatuba - UNESP.

Introduction: Root canal treatment plays a fundamental role in abolishing infections in teeth showing pulp necrosis. Objective: We aimed to evaluate the clinical and radiographic efficacy of root canal treatment for teeth with chronic periapical lesions, which was performed by students of Undergraduate Dentistry, Faculty of Dentistry, Campus Araçatuba - UNESP. Material and Method: We selected 100 patients who had teeth with chronic periapical lesions. After biomechanical preparation, the root canal receiving of calcium hydroxide intracanal dressing during the 14 days. The root canals were filled with a calcium hydroxide-based endodontic sealer. Follow-up examinations were performed for at least 8 months. Result: An analysis of the results showed total repair in 78.46% of the cases and no evidence of repair in 21.54% of the cases. Conclusion: Repair occurred in the teeth with chronic periapical lesions treated by students of Undergraduate Dentistry, Faculty of Dentistry, Campus Araçatuba - UNESP.

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.

[Comparative light microscopy study of periapical and pulpal response to different stimuli (2)]. / Estudio comparativo en microscopia óptica de la respuesta periapical y pulpar ante dos estímulos diferentes (segunda parte).

In this communication, the second of three we report the periapical and pulpal response against electric stimulation and pulpal exposure, after 20 weeks. We analyzed the quantitative cellular findings encountered in the periapical areas are presented.

Root canal treatment with calcium hydroxide. I. Effect of overfilling and refilling.

Root canals of dog premolar teeth were negotiated and overfilled with calcium hydroxide paste. After 30 days, half of the treated teeth were refilled up to the apical limit. Root canals not filled were considered as the control group. Ninety days after the first treatment, histologic analysis showed more favorable results in the refilled root canals. The overfilling elicits calcium hydroxide resorption and the ingrowth of periapical connective tissue into the root canal.

[Alternative solutions for postoperative pain in teeth with necrotic pulp]. / Alternativas de solución para el dolor posoperatorio en dientes con pulpa necrótica.

Both the literature and clinical experience have verified that necrotic root canals, with or without periapical lesion, display a confusing response to the various tests for pulp vitality. As suggested by clinical and histopathological research studies, these lesions are due to a defense reaction from the periapical connective tissue, in response to bacterial infections which alter host tissues. Diminishing the frequency of postoperative pain in endodontic treatment is currently a leading concern, and this study aimed to evaluate the different variables involved in root canal therapy, so as to recommend the most suitable approach, without losing sight of the main goal at hand: a successful endodontic treatment. The present study was performed on 200 necrotic root canals, using frontal teeth, upper and lower premolars and molars, both with straight or curved canals. Avoiding damage to the periapical regions, the study concluded, is of prime importance in lowering the frequency of postoperatory pain. Also, the presence of periapical pain is vitally important in the appearance of postoperatory pain, and it is in such cases that cleansing must be adopted as a routine clinical procedure.

[Comparative light microscopy study of periapical and pulpal response to different stimuli (1)]. / Estudio comparativo en microscopia optica de la respuesta periapical y pulpar ante dos estimulos diferentes (Primera parte).

A comparative study of pulpal and periapical responses to pulpal exposure and electric stimulus. In this report we communicate the changes found in the pulp and supporting tissues.

[Electron microscopic study on the tissue reaction after root canal filling following artificial periapical lesions--about periapical lesions induced by carrageenin].

Although a number of reports on the formation of periapical lesions have been down, little study on the healing stage of this one is seen. Therefore, the aim of this study was to investigate the changes of the fine structure of the healing stage of the artificial periapical lesions after root canal filling and to make an experimental model for the further screening test of various kinds of medicaments and materials for root canal treatment and root canal filling. In this study, the first mandibular molars of male Wistar strain rats were used. Periapical lesions were induced by 0.5% carrageenin and after three weeks, the root canals of the first molars were filled with gutta-percha points and sealers. Then, the healing stage of the periapical lesion was observed light microscopically, electron-microscopically and enzyme (alkaline phosphatase, ALP, and acid phosphatase, ACP)-histochemically. The results were as follows after the root canal filling with carrageenins: 1. At 1 to 7 days, a great number of neutrophils and histiocytes were observed and expansion of periapical lesions caused by the irritation followed by root canal filling was observed. 2. At 2 to 3 weeks, a great number of leukocytes, histiocytes and fibroblasts were observed in the vicinity of the root apex. 3. At 4 to 5 weeks, a great number of histiocytes and mast cells were observed and granulated tissues of the periapical lesions had a tendency to become fibrosis and new calcified cement increased at the root apex. 4. At 7 to 10 weeks, the fibroblast granulation tissue around the periapical lesions synthesized active collagen fibers and the deposition of new alveolar bone was seen within the resorbed alveolar bone. 5. At 15 to 20 weeks, the periapical lesions could be thought to be healing histopathologically although some of inflammatory cells were seen 20 weeks after treatment. 6. At 10 weeks, strong positive responses of ALP were recognized. At 20 weeks, the general appearance of both the ALP and ACP staining showed almost the same response as that of normal periodontium. 7. As for the prognosis, "over filling" showed better healing than that of "under filling". 8. In the case which the root apex was fractured, inflammation lasted for a long period.

Periodontium response to a root canal condensing device (Endotec).

Two Macaca (fascicularis) monkeys were used to study the effect of two warm endodontic condensation techniques (Endotec and vertical condensation method) on periodontal tissues. The specimens were histologically evaluated at 3 and 32 days after the endodontic treatments were completed. In this study the periodontium was divided into coronal, middle, and apical thirds. Results indicated that there was no heat-related damage to periodontal tissues from either of the two methods employed. However, some Endotec specimens generated small, reactive inflammatory infiltrates that were restricted to the root canal opening or adjacent periodontal membrane. Similarly, some vertical condensation specimens developed periapical inflammatory processes as well, but they were more extensive and comprised the alveolar bone and marrow spaces.