Simona Loghin - Academia.edu (original) (raw)
Papers by Simona Loghin
Journal of Endodontics, Aug 1, 2018
This article describes a case of large persistent posttreatment apical periodontitis associated w... more This article describes a case of large persistent posttreatment apical periodontitis associated with 2 maxillary incisors, which was successfully managed by periradicular surgery. Histobacteriologic analysis revealed that the lesion was a granuloma that contained in its body a very large actinomycoticlike colony surrounded by accumulations of polymorphonuclear leukocytes and showing no direct communication with the root canal systems from both teeth. One incisor had no evidence of persistent intraradicular infection, whereas the other exhibited some residual dentinal tubule infection in the apical canal, which may have not significantly contributed to persistent inflammation given the organization and agglomeration of inflammatory cells around the large extraradicular bacterial colony. Findings showed that the main cause of persistent disease was the extraradicular infection in the form of a large bacterial floc, apparently independent of an intraradicular infection and as such only solved by surgery.
Journal of Dentistry, Jun 1, 2018
Introduction: The present study reported the histological events that occurred in the radicular p... more Introduction: The present study reported the histological events that occurred in the radicular pulp of human mature teeth in the presence of medium/deep untreated caries lesions, and those teeth with restorations or direct pulp capping, with particular emphasis on the morphology of the canal wall dentine and the odontoblast layer. Methods: Sixty-two teeth with medium/deep caries lesions, extensive restorations or after application of a direct pulp capping procedure were obtained from 57 subjects. Fourteen intact mature teeth served as controls. Stained serial sections were examined for the pulp conditions of the coronal pulp. The teeth were classified as those with pulpal inflammation, or those with healed pulps. Histological changes that occurred in the roots at the pulpdentine junction were investigated in detail. Results: All teeth (100%) in the experimental group showed pathologic changes in the radicular pulp, with varying amounts of tertiary dentine on the canal walls and absence of odontoblasts. These changes were identified from different portions of the canal wall surface. Non-adherent calcifications in the pulp tissue were observed in more than half of the specimens. Changes that deviate from classically-perceived histological relationships of the pulp-dentine complex were also observed in the radicular pulps of 33.7% of the control teeth. Conclusion: When challenged by bacteria and bacterial by-products invading dentinal tubules, odontoblasts in the radicular pulp may undergo cell death, possibly by apoptosis. This phenomenon may be caused by progressive root-ward diffusion of bacterial by-products, cytokines or reactive oxygen species through the pulp connective tissue. Clinical significance: Although the vitality of the dental pulp in teeth with deep dentinal caries may be maintained with direct pulp capping or pulpotomy, the repair tissue that is formed resembles mineralised fibrous connective tissues more than true tubular dentine.
Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, cariou... more Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, carious infection is the primary etiology of pulpal and periapical disease. When caries involves the irritation dentin, the pulp becomes irreversibly inflamed. If untreated, the pulp will be infected and colonized by oral microbes. The infected pulp is not capable of self-healing because of lack of collateral circulation and restricted blood supply to effectively deliver innate and adaptive immune defense mechanisms. As pulp infection/inflammation spreads apically, periapical inflammation develops. Apical periodontitis is the extension of apical pulpitis. Usually, microbes from the infected canal would not establish infectious process in the periapical tissues, which have plenty of collateral circulation to deliver cellular and humoral defense components. When the pulp becomes infected, nonsurgical root canal therapy should be initiated as soon as possible to prevent the development of apical periodontitis. In teeth with infected pulp and apical periodontitis, the microbes have well-established infection in the canal system, form biofilm on the canal walls and isthmus, and have penetrated into the dentinal tubules and lateral/accessory canals. Therefore, it is difficult to eliminate the majority of microbes in the root canal system by chemomechanical debridement. Accordingly, teeth with irreversible pulpitis without apical periodontitis have a better prognosis than the teeth with apical periodontitis after nonsurgical root canal therapy. Understanding the pathogenesis of pulpal and periapical disease will guide the clinicians to take appropriate treatment procedures to achieve satisfactory wound healing of the disease.
Journal of Endodontics, Aug 1, 2014
Introduction: Root resorption is a frequent finding in teeth with apical periodontitis. In cases ... more Introduction: Root resorption is a frequent finding in teeth with apical periodontitis. In cases of severe apical periodontitis, root resorption may involve not only cementum but also dentin. Resorbed tooth structures can only be repaired with cementum because stem cells in the periradicular tissues are not capable of differentiating into odontoblasts. This article reports the repair of extensive apical root resorption associated with apical periodontitis 25 years after treatment. Methods: A 51-year-old man presented with pulp necrosis and symptomatic apical periodontitis in tooth #7. The periapical radiograph showed a large radiolucent periradicular lesion and severe root resorption. Nonsurgical root canal therapy was performed. Twenty-five years after treatment, a crown fracture developed, and the tooth could not be restored. The periapical radiograph revealed complete healing of the previous apical periodontitis lesion and restoration of the resorbed root structure. The tooth was removed and examined histologically. Results: The apical canal was almost completely filled with a cementumlike tissue with some strands of entrapped vital uninflamed connective tissue. Areas of cementum and dentin resorption in the apical third were repaired by a combination of cellular and acellular cementum to which periodontal ligament fibers were attached. Conclusions: Root resorption caused by apical periodontitis can be restored almost to its normal structure after adequate nonsurgical root canal treatment that succeeded in controlling infection. The mechanisms behind this process are not clear but probably involve signaling pathways regulating root development, cell-cell and cell-matrix interaction, and morphogens.
Journal of Dentistry, Sep 1, 2014
Journal of Endodontics, May 1, 2013
This article describes a case in which signs and symptoms persisted in spite of the endodontic tr... more This article describes a case in which signs and symptoms persisted in spite of the endodontic treatment following high standards to characterize a short-term failure. After several appointments of root canal treatment in an attempt to resolve persistent symptoms, including 106 days of calcium hydroxide intracanal medication, periradicular surgery was performed, and the root apex and the lesion were subjected to histologic and histobacteriologic analyses. The lesion was diagnosed as a cyst, and the main root canal was free of bacteria and debris. The cause of the short-term failure was an exuberant bacterial biofilm colonizing a lateral canal in the apical root segment. This case report highlights one of the major problems of modern endodontic therapy; bacteria located in areas distant from the main root canal can remain unaffected by treatment procedures and maintain disease. The challenge for researchers and clinicians that arises from this problem is to develop strategies, instruments, or substances that can reach those areas and achieve sufficient reduction in the infectious bioburden to permit predictable periradicular healing.
Journal of Endodontics, 2014
Introduction: Histologic studies of teeth from animal models of revascularization/revitalization ... more Introduction: Histologic studies of teeth from animal models of revascularization/revitalization are available; however, specimens from human studies are lacking. The nature of tissues formed in the canal of human revascularized/revitalized teeth was not well established. Methods: An immature mandibular premolar with infected necrotic pulp and a chronic apical abscess was treated with revascularization/revitalization procedures. At both the 18-month and 2-year follow-up visits, radiographic examination showed complete resolution of the periapical lesion, narrowing of the root apex without root lengthening, and minimal thickening of the canal walls. The revascularized/revitalized tooth was removed because of orthodontic treatment and processed for histologic examination. Results: The large canal space of revascularized/revitalized tooth was not empty and filled with fibrous connective tissue. The apical closure was caused by cementum deposition without dentin. Some cementum-like tissue was formed on the canal dentin walls. Inflammatory cells were observed in the coronal and middle third of revascularized/revitalized tissue. Conclusions: In the present case, the tissue formed in the canal of a human revascularized/revitalized tooth was soft connective tissue similar to that in the periodontal ligament and cementum-like or bonelike hard tissue, which is comparable with the histology observed in the canals of teeth from animal models of revascularization/revitalization.
Journal of Endodontics, Apr 1, 2014
Introduction: This article reports on the morphologic features and the frequency of ciliated epit... more Introduction: This article reports on the morphologic features and the frequency of ciliated epithelium in apical cysts and discusses its origin. Methods: The study material consisted of 167 human apical periodontitis lesions obtained consecutively from patients presenting for treatment during a period of 12 years in a dental practice operated by one of the authors. All of the lesions were obtained still attached to the root apices of teeth with untreated (93 lesions) or treated canals (74 lesions). The former were obtained by extraction and the latter by extraction or apical surgery. Specimens were processed for histopathologic and histobacteriologic analyses. Lesions were classified, and the type of epithelium, if present, was recorded. Results: Of the lesions analyzed, 49 (29%) were diagnosed as cysts. Of these, 26 (53%) were found in untreated teeth, and 23 (47%) related to root canal-treated teeth. Ciliated columnar epithelium was observed partially or completely lining the cyst wall in 4 cysts, and all of them occurred in untreated maxillary molars. Three of these lesions were categorized as pocket cysts, and the other was a true cyst. Conclusions: Ciliated columnar epithelium-lined cysts corresponded to approximately 2% of the apical periodontitis lesions and 8% of the cysts of endodontic origin in the population studied. This epithelium is highly likely to have a sinus origin in the majority of cases. However, the possibility of prosoplasia or upgraded differentiation into ciliated epithelium from the typical cystic lining squamous epithelium may also be considered.
Journal of Endodontics, Mar 1, 2018
Introduction: This histobacteriologic study described the pattern of intraradicular and extraradi... more Introduction: This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses. Methods: The material comprised biopsy specimens from 24 (8 untreated and 16 treated) roots of teeth associated with apical periodontitis and a sinus tract. Specimens were obtained by periradicular surgery or extraction and were processed for histobacteriologic and histopathologic methods. Results: Bacteria were found in the apical root canal system of all specimens, in the main root canal (22 teeth) and within ramifications (17 teeth). Four cases showed no extraradicular infection. Extraradicular bacteria occurred as a biofilm attached to the outer root surface in 17 teeth (5 untreated and 12 treated teeth), as actinomycotic colonies in 2 lesions, and as planktonic cells in 2 lesions. Extraradicular calculus formation (mineralized biofilm) was evident in 10 teeth. Conclusions: Teeth with chronic apical abscesses and sinus tracts showed a very complex infectious pattern in the apical root canal system and periapical lesion, with a predominance of biofilms.
Journal of Endodontics, Feb 1, 2014
Mechanical debridement plays an important role in eliminating intracanal bacteria, such as biofil... more Mechanical debridement plays an important role in eliminating intracanal bacteria, such as biofilm on the canal walls and bacteria in the dentinal tubules. Mechanical debridement is not recommended for root canal disinfection in revascularization/revitalization therapy. Here we report a failed revascularization/revitalization case, which could be due to inadequate root canal disinfection without mechanical removal of biofilm and bacteria in dentinal tubules. A 6-year-old boy had a traumatic injury to tooth #9, which was avulsed and replanted within 40 minutes. The tooth subsequently developed a local swelling in the periapical area. The patient was referred to the Postgraduate Endodontic Clinic for revascularization/revitalization therapy on tooth #9. The treated tooth remained asymptomatic for 16 months and then developed pain and local periapical swelling. The oral surgeon extracted the revascularized/revitalized tooth. On request, the extracted tooth was processed for histologic and histobacteriologic examination. The tissue in the canal was completely destroyed. Most bacteria were observed in the apical portion and not in the coronal portion of the canal and formed biofilm on the canal walls and penetrated into the dentinal tubules. On the basis of histobacteriologic observations, the failure of revascularized/revitalized tooth could be due to inadequate root canal disinfection without mechanical debridement. It may be important to perform mechanical debridement as part of the revascularization/revitalization therapy to disrupt the biofilm on the canal walls and remove bacteria in the dentinal tubules because revascularization/revitalization therapy is able to increase thickening of the canal walls.
Journal of Dentistry, 2017
Descriptions of the pathologic changes in the pulp and associated apical structures of human imma... more Descriptions of the pathologic changes in the pulp and associated apical structures of human immature teeth in response to deep caries are lacking in the literature. This article describes the histologic events associated with the radicular pulp and the apical tissues of human immature teeth following pulp inflammation and necrosis. Twelve immature teeth with destructive caries lesions were obtained from 8 patients. Two intact immature teeth served as controls. Teeth were extracted for reasons not related to this study and immediately processed for histopathologic and histobacteriologic analyses. Serial sections were examined for the pulp conditions and classified as reversible or irreversible pulp inflammation, or pulp necrosis. Other histologic parameters were also evaluated. In the 3 cases with reversible pulp inflammation, tissue in the pulp chamber showed mild to moderate inflammation and tertiary dentin formation related to tubules involved in the caries process. Overall, the radicular pulp tissue, apical papilla and Hertwig's epithelial root sheath (HERS) exhibited characteristics of normality. In the 3 cases with irreversible pulp inflammation, the pulps were exposed and severe inflammation occurred in the pulp chamber, with minor areas of necrosis and infection. Large areas of the canal walls were free from odontoblasts and lined by an atubular mineralized tissue. The apical papilla showed extremely reduced cellularity or lack of cells and HERS was discontinuous or absent. In the 6 cases with pulp necrosis, the coronal and radicular pulp tissue was necrotic and colonized by bacterial biofilms. The apical papilla could not be discerned, except for one case. HERS was absent in the necrotic cases. While immature teeth with reversible pulpitis showed histologic features almost similar to normal teeth in the canal and in the apical region, those with irreversible pulpitis and necrosis exhibited significant alterations not only in the radicular pulp but also in the apical tissues, including the apical papilla and HERS. Alterations in the radicular pulp and apical tissues help explain the outcome of current regenerative/reparative therapies and should be taken into account when devising more predictable therapeutic protocols for teeth with incomplete root formation.
Journal of Endodontics, Mar 1, 2015
Introduction: The diagnosis and treatment planning of cracked teeth depend on the understanding o... more Introduction: The diagnosis and treatment planning of cracked teeth depend on the understanding of how cracks affect the surrounding tissues. This study evaluated the dentin and pulp conditions in teeth affected by cracks and attrition. Methods: Specimens under investigation included 12 cracked posterior teeth and 8 teeth with severe attrition. These teeth were obtained consecutively in a private practice and were extracted for reasons not related to this study. Teeth were processed for histopathologic and histobacteriologic analyses. Results: Cracks were histologically detected in all specimens, including the teeth with severe attrition. The cracks in all teeth were colonized by bacterial biofilms. One tooth showed several craze lines in the enamel, one of which reached dentin to a shallow depth. In some teeth, the crack ended in the dentin. Dentinal tubules were invaded by bacteria, especially when the crack extended perpendicularly into the dentin. Severe accumulations of inflammatory cells were present in the pulp zone subjacent to tubules involved with the crack. In many cases, the crack extended to the pulp, leading to reactions with intensities ranging from acute inflammation to total pulpal necrosis. Symptoms occurred in most cases in which the pulp was affected. In some cases, polymorphonuclear neutrophils were seen migrating from the pulp into the crack space and facing the bacterial biofilm located therein. Severe pulp reactions were also observed when the crack extended to the pulp chamber floor. Conclusions: Cracks are always colonized with bacterial biofilms. The pulp tissue response varies according to the location, direction, and extent of the crack.
Australian Endodontic Journal, Aug 14, 2017
The purpose of this article was to report a case of untreated apical periodontitis resulting in s... more The purpose of this article was to report a case of untreated apical periodontitis resulting in severe late complications. A patient with an asymptomatic crowned root canal-treated mandibular molar revealing a radiographic substandard endodontic treatment and a slight periapical radiolucency was made aware of the treatment options and opted for no treatment. The lesion slightly increased in size after 6 years, but the tooth remained asymptomatic and endodontic retreatment was again refused. After 4 more years, the patient presented with an abscess and severe pain, complicated by paraesthesia of the left chin and lip. Radiographic examination revealed that the lesion had increased considerably to involve the mandibular canal. The treatment protocol included long-term intracanal medication with calcium hydroxide and follow-ups revealed complete resolution of the periapical radiolucency and the paraesthesia had completely subsided.
Journal of Endodontics, Oct 1, 2018
This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected ... more This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected teeth, resulting in exposure of the root apex to the oral cavity. Both cases consisted of maxillary incisors with pulp necrosis and radiographic/tomographic evidence of apical periodontitis. Clinically, the root apex was exposed to the oral cavity through a fenestration in both bone and mucosa and covered with bacterial plaque and calculus. These teeth were treated by a combination of nonsurgical and surgical endodontic treatment. During surgery, the root apices were resected to within the alveolus and the fenestrated area covered by the flap. Specimens consisting of the root apex and surrounding soft tissues were subjected to histopathological and histobacteriological analyses. Histobacteriological analysis revealed extensive resorptive defects on the root apices filled with thick bacterial biofilm, irregular detachment of the cementum layers with consequent infection of the underlying spaces, and heavy infection in the apical foramina. The soft tissue specimens exhibited no or minimal inflammation. The 2 cases showed satisfactory postsurgical healing of the hard and soft tissues. Both cases of mucosal fenestration showed root apices covered with dense bacterial biofilms and associated with a bone crypt with no significant inflammatory tissue therein. The 2 cases were successfully treated by conservative approaches involving a combination of nonsurgical and surgical endodontic treatment with root-end resection.
Journal of Dentistry, 2018
Introduction: The present study reported the histological events that occurred in the radicular p... more Introduction: The present study reported the histological events that occurred in the radicular pulp of human mature teeth in the presence of medium/deep untreated caries lesions, and those teeth with restorations or direct pulp capping, with particular emphasis on the morphology of the canal wall dentine and the odontoblast layer. Methods: Sixty-two teeth with medium/deep caries lesions, extensive restorations or after application of a direct pulp capping procedure were obtained from 57 subjects. Fourteen intact mature teeth served as controls. Stained serial sections were examined for the pulp conditions of the coronal pulp. The teeth were classified as those with pulpal inflammation, or those with healed pulps. Histological changes that occurred in the roots at the pulpdentine junction were investigated in detail. Results: All teeth (100%) in the experimental group showed pathologic changes in the radicular pulp, with varying amounts of tertiary dentine on the canal walls and absence of odontoblasts. These changes were identified from different portions of the canal wall surface. Non-adherent calcifications in the pulp tissue were observed in more than half of the specimens. Changes that deviate from classically-perceived histological relationships of the pulp-dentine complex were also observed in the radicular pulps of 33.7% of the control teeth. Conclusion: When challenged by bacteria and bacterial by-products invading dentinal tubules, odontoblasts in the radicular pulp may undergo cell death, possibly by apoptosis. This phenomenon may be caused by progressive root-ward diffusion of bacterial by-products, cytokines or reactive oxygen species through the pulp connective tissue. Clinical significance: Although the vitality of the dental pulp in teeth with deep dentinal caries may be maintained with direct pulp capping or pulpotomy, the repair tissue that is formed resembles mineralised fibrous connective tissues more than true tubular dentine.
Journal of endodontics, 2018
This article describes a case of large persistent posttreatment apical periodontitis associated w... more This article describes a case of large persistent posttreatment apical periodontitis associated with 2 maxillary incisors, which was successfully managed by periradicular surgery. Histobacteriologic analysis revealed that the lesion was a granuloma that contained in its body a very large actinomycoticlike colony surrounded by accumulations of polymorphonuclear leukocytes and showing no direct communication with the root canal systems from both teeth. One incisor had no evidence of persistent intraradicular infection, whereas the other exhibited some residual dentinal tubule infection in the apical canal, which may have not significantly contributed to persistent inflammation given the organization and agglomeration of inflammatory cells around the large extraradicular bacterial colony. Findings showed that the main cause of persistent disease was the extraradicular infection in the form of a large bacterial floc, apparently independent of an intraradicular infection and as such only...
Journal of endodontics, 2018
This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected ... more This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected teeth, resulting in exposure of the root apex to the oral cavity. Both cases consisted of maxillary incisors with pulp necrosis and radiographic/tomographic evidence of apical periodontitis. Clinically, the root apex was exposed to the oral cavity through a fenestration in both bone and mucosa and covered with bacterial plaque and calculus. These teeth were treated by a combination of nonsurgical and surgical endodontic treatment. During surgery, the root apices were resected to within the alveolus and the fenestrated area covered by the flap. Specimens consisting of the root apex and surrounding soft tissues were subjected to histopathological and histobacteriological analyses. Histobacteriological analysis revealed extensive resorptive defects on the root apices filled with thick bacterial biofilm, irregular detachment of the cementum layers with consequent infection of the underlying ...
Journal of endodontics, Mar 1, 2018
This histobacteriologic study described the pattern of intraradicular and extraradicular infectio... more This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses. The material comprised biopsy specimens from 24 (8 untreated and 16 treated) roots of teeth associated with apical periodontitis and a sinus tract. Specimens were obtained by periradicular surgery or extraction and were processed for histobacteriologic and histopathologic methods. Bacteria were found in the apical root canal system of all specimens, in the main root canal (22 teeth) and within ramifications (17 teeth). Four cases showed no extraradicular infection. Extraradicular bacteria occurred as a biofilm attached to the outer root surface in 17 teeth (5 untreated and 12 treated teeth), as actinomycotic colonies in 2 lesions, and as planktonic cells in 2 lesions. Extraradicular calculus formation (mineralized biofilm) was evident in 10 teeth. Teeth with chronic apical abscesses and sinus tracts showed a very complex infecti...
Endodontic Prognosis, 2016
Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, cariou... more Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, carious infection is the primary etiology of pulpal and periapical disease. When caries involves the irritation dentin, the pulp becomes irreversibly inflamed. If untreated, the pulp will be infected and colonized by oral microbes. The infected pulp is not capable of self-healing because of lack of collateral circulation and restricted blood supply to effectively deliver innate and adaptive immune defense mechanisms. As pulp infection/inflammation spreads apically, periapical inflammation develops. Apical periodontitis is the extension of apical pulpitis. Usually, microbes from the infected canal would not establish infectious process in the periapical tissues, which have plenty of collateral circulation to deliver cellular and humoral defense components. When the pulp becomes infected, nonsurgical root canal therapy should be initiated as soon as possible to prevent the development of apical periodontitis. In teeth with infected pulp and apical periodontitis, the microbes have well-established infection in the canal system, form biofilm on the canal walls and isthmus, and have penetrated into the dentinal tubules and lateral/accessory canals. Therefore, it is difficult to eliminate the majority of microbes in the root canal system by chemomechanical debridement. Accordingly, teeth with irreversible pulpitis without apical periodontitis have a better prognosis than the teeth with apical periodontitis after nonsurgical root canal therapy. Understanding the pathogenesis of pulpal and periapical disease will guide the clinicians to take appropriate treatment procedures to achieve satisfactory wound healing of the disease.
Journal of Dentistry, 2017
Descriptions of the pathologic changes in the pulp and associated apical structures of human imma... more Descriptions of the pathologic changes in the pulp and associated apical structures of human immature teeth in response to deep caries are lacking in the literature. This article describes the histologic events associated with the radicular pulp and the apical tissues of human immature teeth following pulp inflammation and necrosis. Twelve immature teeth with destructive caries lesions were obtained from 8 patients. Two intact immature teeth served as controls. Teeth were extracted for reasons not related to this study and immediately processed for histopathologic and histobacteriologic analyses. Serial sections were examined for the pulp conditions and classified as reversible or irreversible pulp inflammation, or pulp necrosis. Other histologic parameters were also evaluated. In the 3 cases with reversible pulp inflammation, tissue in the pulp chamber showed mild to moderate inflammation and tertiary dentin formation related to tubules involved in the caries process. Overall, the radicular pulp tissue, apical papilla and Hertwig's epithelial root sheath (HERS) exhibited characteristics of normality. In the 3 cases with irreversible pulp inflammation, the pulps were exposed and severe inflammation occurred in the pulp chamber, with minor areas of necrosis and infection. Large areas of the canal walls were free from odontoblasts and lined by an atubular mineralized tissue. The apical papilla showed extremely reduced cellularity or lack of cells and HERS was discontinuous or absent. In the 6 cases with pulp necrosis, the coronal and radicular pulp tissue was necrotic and colonized by bacterial biofilms. The apical papilla could not be discerned, except for one case. HERS was absent in the necrotic cases. While immature teeth with reversible pulpitis showed histologic features almost similar to normal teeth in the canal and in the apical region, those with irreversible pulpitis and necrosis exhibited significant alterations not only in the radicular pulp but also in the apical tissues, including the apical papilla and HERS. Alterations in the radicular pulp and apical tissues help explain the outcome of current regenerative/reparative therapies and should be taken into account when devising more predictable therapeutic protocols for teeth with incomplete root formation.
Journal of Endodontics, Aug 1, 2018
This article describes a case of large persistent posttreatment apical periodontitis associated w... more This article describes a case of large persistent posttreatment apical periodontitis associated with 2 maxillary incisors, which was successfully managed by periradicular surgery. Histobacteriologic analysis revealed that the lesion was a granuloma that contained in its body a very large actinomycoticlike colony surrounded by accumulations of polymorphonuclear leukocytes and showing no direct communication with the root canal systems from both teeth. One incisor had no evidence of persistent intraradicular infection, whereas the other exhibited some residual dentinal tubule infection in the apical canal, which may have not significantly contributed to persistent inflammation given the organization and agglomeration of inflammatory cells around the large extraradicular bacterial colony. Findings showed that the main cause of persistent disease was the extraradicular infection in the form of a large bacterial floc, apparently independent of an intraradicular infection and as such only solved by surgery.
Journal of Dentistry, Jun 1, 2018
Introduction: The present study reported the histological events that occurred in the radicular p... more Introduction: The present study reported the histological events that occurred in the radicular pulp of human mature teeth in the presence of medium/deep untreated caries lesions, and those teeth with restorations or direct pulp capping, with particular emphasis on the morphology of the canal wall dentine and the odontoblast layer. Methods: Sixty-two teeth with medium/deep caries lesions, extensive restorations or after application of a direct pulp capping procedure were obtained from 57 subjects. Fourteen intact mature teeth served as controls. Stained serial sections were examined for the pulp conditions of the coronal pulp. The teeth were classified as those with pulpal inflammation, or those with healed pulps. Histological changes that occurred in the roots at the pulpdentine junction were investigated in detail. Results: All teeth (100%) in the experimental group showed pathologic changes in the radicular pulp, with varying amounts of tertiary dentine on the canal walls and absence of odontoblasts. These changes were identified from different portions of the canal wall surface. Non-adherent calcifications in the pulp tissue were observed in more than half of the specimens. Changes that deviate from classically-perceived histological relationships of the pulp-dentine complex were also observed in the radicular pulps of 33.7% of the control teeth. Conclusion: When challenged by bacteria and bacterial by-products invading dentinal tubules, odontoblasts in the radicular pulp may undergo cell death, possibly by apoptosis. This phenomenon may be caused by progressive root-ward diffusion of bacterial by-products, cytokines or reactive oxygen species through the pulp connective tissue. Clinical significance: Although the vitality of the dental pulp in teeth with deep dentinal caries may be maintained with direct pulp capping or pulpotomy, the repair tissue that is formed resembles mineralised fibrous connective tissues more than true tubular dentine.
Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, cariou... more Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, carious infection is the primary etiology of pulpal and periapical disease. When caries involves the irritation dentin, the pulp becomes irreversibly inflamed. If untreated, the pulp will be infected and colonized by oral microbes. The infected pulp is not capable of self-healing because of lack of collateral circulation and restricted blood supply to effectively deliver innate and adaptive immune defense mechanisms. As pulp infection/inflammation spreads apically, periapical inflammation develops. Apical periodontitis is the extension of apical pulpitis. Usually, microbes from the infected canal would not establish infectious process in the periapical tissues, which have plenty of collateral circulation to deliver cellular and humoral defense components. When the pulp becomes infected, nonsurgical root canal therapy should be initiated as soon as possible to prevent the development of apical periodontitis. In teeth with infected pulp and apical periodontitis, the microbes have well-established infection in the canal system, form biofilm on the canal walls and isthmus, and have penetrated into the dentinal tubules and lateral/accessory canals. Therefore, it is difficult to eliminate the majority of microbes in the root canal system by chemomechanical debridement. Accordingly, teeth with irreversible pulpitis without apical periodontitis have a better prognosis than the teeth with apical periodontitis after nonsurgical root canal therapy. Understanding the pathogenesis of pulpal and periapical disease will guide the clinicians to take appropriate treatment procedures to achieve satisfactory wound healing of the disease.
Journal of Endodontics, Aug 1, 2014
Introduction: Root resorption is a frequent finding in teeth with apical periodontitis. In cases ... more Introduction: Root resorption is a frequent finding in teeth with apical periodontitis. In cases of severe apical periodontitis, root resorption may involve not only cementum but also dentin. Resorbed tooth structures can only be repaired with cementum because stem cells in the periradicular tissues are not capable of differentiating into odontoblasts. This article reports the repair of extensive apical root resorption associated with apical periodontitis 25 years after treatment. Methods: A 51-year-old man presented with pulp necrosis and symptomatic apical periodontitis in tooth #7. The periapical radiograph showed a large radiolucent periradicular lesion and severe root resorption. Nonsurgical root canal therapy was performed. Twenty-five years after treatment, a crown fracture developed, and the tooth could not be restored. The periapical radiograph revealed complete healing of the previous apical periodontitis lesion and restoration of the resorbed root structure. The tooth was removed and examined histologically. Results: The apical canal was almost completely filled with a cementumlike tissue with some strands of entrapped vital uninflamed connective tissue. Areas of cementum and dentin resorption in the apical third were repaired by a combination of cellular and acellular cementum to which periodontal ligament fibers were attached. Conclusions: Root resorption caused by apical periodontitis can be restored almost to its normal structure after adequate nonsurgical root canal treatment that succeeded in controlling infection. The mechanisms behind this process are not clear but probably involve signaling pathways regulating root development, cell-cell and cell-matrix interaction, and morphogens.
Journal of Dentistry, Sep 1, 2014
Journal of Endodontics, May 1, 2013
This article describes a case in which signs and symptoms persisted in spite of the endodontic tr... more This article describes a case in which signs and symptoms persisted in spite of the endodontic treatment following high standards to characterize a short-term failure. After several appointments of root canal treatment in an attempt to resolve persistent symptoms, including 106 days of calcium hydroxide intracanal medication, periradicular surgery was performed, and the root apex and the lesion were subjected to histologic and histobacteriologic analyses. The lesion was diagnosed as a cyst, and the main root canal was free of bacteria and debris. The cause of the short-term failure was an exuberant bacterial biofilm colonizing a lateral canal in the apical root segment. This case report highlights one of the major problems of modern endodontic therapy; bacteria located in areas distant from the main root canal can remain unaffected by treatment procedures and maintain disease. The challenge for researchers and clinicians that arises from this problem is to develop strategies, instruments, or substances that can reach those areas and achieve sufficient reduction in the infectious bioburden to permit predictable periradicular healing.
Journal of Endodontics, 2014
Introduction: Histologic studies of teeth from animal models of revascularization/revitalization ... more Introduction: Histologic studies of teeth from animal models of revascularization/revitalization are available; however, specimens from human studies are lacking. The nature of tissues formed in the canal of human revascularized/revitalized teeth was not well established. Methods: An immature mandibular premolar with infected necrotic pulp and a chronic apical abscess was treated with revascularization/revitalization procedures. At both the 18-month and 2-year follow-up visits, radiographic examination showed complete resolution of the periapical lesion, narrowing of the root apex without root lengthening, and minimal thickening of the canal walls. The revascularized/revitalized tooth was removed because of orthodontic treatment and processed for histologic examination. Results: The large canal space of revascularized/revitalized tooth was not empty and filled with fibrous connective tissue. The apical closure was caused by cementum deposition without dentin. Some cementum-like tissue was formed on the canal dentin walls. Inflammatory cells were observed in the coronal and middle third of revascularized/revitalized tissue. Conclusions: In the present case, the tissue formed in the canal of a human revascularized/revitalized tooth was soft connective tissue similar to that in the periodontal ligament and cementum-like or bonelike hard tissue, which is comparable with the histology observed in the canals of teeth from animal models of revascularization/revitalization.
Journal of Endodontics, Apr 1, 2014
Introduction: This article reports on the morphologic features and the frequency of ciliated epit... more Introduction: This article reports on the morphologic features and the frequency of ciliated epithelium in apical cysts and discusses its origin. Methods: The study material consisted of 167 human apical periodontitis lesions obtained consecutively from patients presenting for treatment during a period of 12 years in a dental practice operated by one of the authors. All of the lesions were obtained still attached to the root apices of teeth with untreated (93 lesions) or treated canals (74 lesions). The former were obtained by extraction and the latter by extraction or apical surgery. Specimens were processed for histopathologic and histobacteriologic analyses. Lesions were classified, and the type of epithelium, if present, was recorded. Results: Of the lesions analyzed, 49 (29%) were diagnosed as cysts. Of these, 26 (53%) were found in untreated teeth, and 23 (47%) related to root canal-treated teeth. Ciliated columnar epithelium was observed partially or completely lining the cyst wall in 4 cysts, and all of them occurred in untreated maxillary molars. Three of these lesions were categorized as pocket cysts, and the other was a true cyst. Conclusions: Ciliated columnar epithelium-lined cysts corresponded to approximately 2% of the apical periodontitis lesions and 8% of the cysts of endodontic origin in the population studied. This epithelium is highly likely to have a sinus origin in the majority of cases. However, the possibility of prosoplasia or upgraded differentiation into ciliated epithelium from the typical cystic lining squamous epithelium may also be considered.
Journal of Endodontics, Mar 1, 2018
Introduction: This histobacteriologic study described the pattern of intraradicular and extraradi... more Introduction: This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses. Methods: The material comprised biopsy specimens from 24 (8 untreated and 16 treated) roots of teeth associated with apical periodontitis and a sinus tract. Specimens were obtained by periradicular surgery or extraction and were processed for histobacteriologic and histopathologic methods. Results: Bacteria were found in the apical root canal system of all specimens, in the main root canal (22 teeth) and within ramifications (17 teeth). Four cases showed no extraradicular infection. Extraradicular bacteria occurred as a biofilm attached to the outer root surface in 17 teeth (5 untreated and 12 treated teeth), as actinomycotic colonies in 2 lesions, and as planktonic cells in 2 lesions. Extraradicular calculus formation (mineralized biofilm) was evident in 10 teeth. Conclusions: Teeth with chronic apical abscesses and sinus tracts showed a very complex infectious pattern in the apical root canal system and periapical lesion, with a predominance of biofilms.
Journal of Endodontics, Feb 1, 2014
Mechanical debridement plays an important role in eliminating intracanal bacteria, such as biofil... more Mechanical debridement plays an important role in eliminating intracanal bacteria, such as biofilm on the canal walls and bacteria in the dentinal tubules. Mechanical debridement is not recommended for root canal disinfection in revascularization/revitalization therapy. Here we report a failed revascularization/revitalization case, which could be due to inadequate root canal disinfection without mechanical removal of biofilm and bacteria in dentinal tubules. A 6-year-old boy had a traumatic injury to tooth #9, which was avulsed and replanted within 40 minutes. The tooth subsequently developed a local swelling in the periapical area. The patient was referred to the Postgraduate Endodontic Clinic for revascularization/revitalization therapy on tooth #9. The treated tooth remained asymptomatic for 16 months and then developed pain and local periapical swelling. The oral surgeon extracted the revascularized/revitalized tooth. On request, the extracted tooth was processed for histologic and histobacteriologic examination. The tissue in the canal was completely destroyed. Most bacteria were observed in the apical portion and not in the coronal portion of the canal and formed biofilm on the canal walls and penetrated into the dentinal tubules. On the basis of histobacteriologic observations, the failure of revascularized/revitalized tooth could be due to inadequate root canal disinfection without mechanical debridement. It may be important to perform mechanical debridement as part of the revascularization/revitalization therapy to disrupt the biofilm on the canal walls and remove bacteria in the dentinal tubules because revascularization/revitalization therapy is able to increase thickening of the canal walls.
Journal of Dentistry, 2017
Descriptions of the pathologic changes in the pulp and associated apical structures of human imma... more Descriptions of the pathologic changes in the pulp and associated apical structures of human immature teeth in response to deep caries are lacking in the literature. This article describes the histologic events associated with the radicular pulp and the apical tissues of human immature teeth following pulp inflammation and necrosis. Twelve immature teeth with destructive caries lesions were obtained from 8 patients. Two intact immature teeth served as controls. Teeth were extracted for reasons not related to this study and immediately processed for histopathologic and histobacteriologic analyses. Serial sections were examined for the pulp conditions and classified as reversible or irreversible pulp inflammation, or pulp necrosis. Other histologic parameters were also evaluated. In the 3 cases with reversible pulp inflammation, tissue in the pulp chamber showed mild to moderate inflammation and tertiary dentin formation related to tubules involved in the caries process. Overall, the radicular pulp tissue, apical papilla and Hertwig's epithelial root sheath (HERS) exhibited characteristics of normality. In the 3 cases with irreversible pulp inflammation, the pulps were exposed and severe inflammation occurred in the pulp chamber, with minor areas of necrosis and infection. Large areas of the canal walls were free from odontoblasts and lined by an atubular mineralized tissue. The apical papilla showed extremely reduced cellularity or lack of cells and HERS was discontinuous or absent. In the 6 cases with pulp necrosis, the coronal and radicular pulp tissue was necrotic and colonized by bacterial biofilms. The apical papilla could not be discerned, except for one case. HERS was absent in the necrotic cases. While immature teeth with reversible pulpitis showed histologic features almost similar to normal teeth in the canal and in the apical region, those with irreversible pulpitis and necrosis exhibited significant alterations not only in the radicular pulp but also in the apical tissues, including the apical papilla and HERS. Alterations in the radicular pulp and apical tissues help explain the outcome of current regenerative/reparative therapies and should be taken into account when devising more predictable therapeutic protocols for teeth with incomplete root formation.
Journal of Endodontics, Mar 1, 2015
Introduction: The diagnosis and treatment planning of cracked teeth depend on the understanding o... more Introduction: The diagnosis and treatment planning of cracked teeth depend on the understanding of how cracks affect the surrounding tissues. This study evaluated the dentin and pulp conditions in teeth affected by cracks and attrition. Methods: Specimens under investigation included 12 cracked posterior teeth and 8 teeth with severe attrition. These teeth were obtained consecutively in a private practice and were extracted for reasons not related to this study. Teeth were processed for histopathologic and histobacteriologic analyses. Results: Cracks were histologically detected in all specimens, including the teeth with severe attrition. The cracks in all teeth were colonized by bacterial biofilms. One tooth showed several craze lines in the enamel, one of which reached dentin to a shallow depth. In some teeth, the crack ended in the dentin. Dentinal tubules were invaded by bacteria, especially when the crack extended perpendicularly into the dentin. Severe accumulations of inflammatory cells were present in the pulp zone subjacent to tubules involved with the crack. In many cases, the crack extended to the pulp, leading to reactions with intensities ranging from acute inflammation to total pulpal necrosis. Symptoms occurred in most cases in which the pulp was affected. In some cases, polymorphonuclear neutrophils were seen migrating from the pulp into the crack space and facing the bacterial biofilm located therein. Severe pulp reactions were also observed when the crack extended to the pulp chamber floor. Conclusions: Cracks are always colonized with bacterial biofilms. The pulp tissue response varies according to the location, direction, and extent of the crack.
Australian Endodontic Journal, Aug 14, 2017
The purpose of this article was to report a case of untreated apical periodontitis resulting in s... more The purpose of this article was to report a case of untreated apical periodontitis resulting in severe late complications. A patient with an asymptomatic crowned root canal-treated mandibular molar revealing a radiographic substandard endodontic treatment and a slight periapical radiolucency was made aware of the treatment options and opted for no treatment. The lesion slightly increased in size after 6 years, but the tooth remained asymptomatic and endodontic retreatment was again refused. After 4 more years, the patient presented with an abscess and severe pain, complicated by paraesthesia of the left chin and lip. Radiographic examination revealed that the lesion had increased considerably to involve the mandibular canal. The treatment protocol included long-term intracanal medication with calcium hydroxide and follow-ups revealed complete resolution of the periapical radiolucency and the paraesthesia had completely subsided.
Journal of Endodontics, Oct 1, 2018
This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected ... more This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected teeth, resulting in exposure of the root apex to the oral cavity. Both cases consisted of maxillary incisors with pulp necrosis and radiographic/tomographic evidence of apical periodontitis. Clinically, the root apex was exposed to the oral cavity through a fenestration in both bone and mucosa and covered with bacterial plaque and calculus. These teeth were treated by a combination of nonsurgical and surgical endodontic treatment. During surgery, the root apices were resected to within the alveolus and the fenestrated area covered by the flap. Specimens consisting of the root apex and surrounding soft tissues were subjected to histopathological and histobacteriological analyses. Histobacteriological analysis revealed extensive resorptive defects on the root apices filled with thick bacterial biofilm, irregular detachment of the cementum layers with consequent infection of the underlying spaces, and heavy infection in the apical foramina. The soft tissue specimens exhibited no or minimal inflammation. The 2 cases showed satisfactory postsurgical healing of the hard and soft tissues. Both cases of mucosal fenestration showed root apices covered with dense bacterial biofilms and associated with a bone crypt with no significant inflammatory tissue therein. The 2 cases were successfully treated by conservative approaches involving a combination of nonsurgical and surgical endodontic treatment with root-end resection.
Journal of Dentistry, 2018
Introduction: The present study reported the histological events that occurred in the radicular p... more Introduction: The present study reported the histological events that occurred in the radicular pulp of human mature teeth in the presence of medium/deep untreated caries lesions, and those teeth with restorations or direct pulp capping, with particular emphasis on the morphology of the canal wall dentine and the odontoblast layer. Methods: Sixty-two teeth with medium/deep caries lesions, extensive restorations or after application of a direct pulp capping procedure were obtained from 57 subjects. Fourteen intact mature teeth served as controls. Stained serial sections were examined for the pulp conditions of the coronal pulp. The teeth were classified as those with pulpal inflammation, or those with healed pulps. Histological changes that occurred in the roots at the pulpdentine junction were investigated in detail. Results: All teeth (100%) in the experimental group showed pathologic changes in the radicular pulp, with varying amounts of tertiary dentine on the canal walls and absence of odontoblasts. These changes were identified from different portions of the canal wall surface. Non-adherent calcifications in the pulp tissue were observed in more than half of the specimens. Changes that deviate from classically-perceived histological relationships of the pulp-dentine complex were also observed in the radicular pulps of 33.7% of the control teeth. Conclusion: When challenged by bacteria and bacterial by-products invading dentinal tubules, odontoblasts in the radicular pulp may undergo cell death, possibly by apoptosis. This phenomenon may be caused by progressive root-ward diffusion of bacterial by-products, cytokines or reactive oxygen species through the pulp connective tissue. Clinical significance: Although the vitality of the dental pulp in teeth with deep dentinal caries may be maintained with direct pulp capping or pulpotomy, the repair tissue that is formed resembles mineralised fibrous connective tissues more than true tubular dentine.
Journal of endodontics, 2018
This article describes a case of large persistent posttreatment apical periodontitis associated w... more This article describes a case of large persistent posttreatment apical periodontitis associated with 2 maxillary incisors, which was successfully managed by periradicular surgery. Histobacteriologic analysis revealed that the lesion was a granuloma that contained in its body a very large actinomycoticlike colony surrounded by accumulations of polymorphonuclear leukocytes and showing no direct communication with the root canal systems from both teeth. One incisor had no evidence of persistent intraradicular infection, whereas the other exhibited some residual dentinal tubule infection in the apical canal, which may have not significantly contributed to persistent inflammation given the organization and agglomeration of inflammatory cells around the large extraradicular bacterial colony. Findings showed that the main cause of persistent disease was the extraradicular infection in the form of a large bacterial floc, apparently independent of an intraradicular infection and as such only...
Journal of endodontics, 2018
This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected ... more This article describes 2 unusual cases of mucosal fenestration associated with necrotic infected teeth, resulting in exposure of the root apex to the oral cavity. Both cases consisted of maxillary incisors with pulp necrosis and radiographic/tomographic evidence of apical periodontitis. Clinically, the root apex was exposed to the oral cavity through a fenestration in both bone and mucosa and covered with bacterial plaque and calculus. These teeth were treated by a combination of nonsurgical and surgical endodontic treatment. During surgery, the root apices were resected to within the alveolus and the fenestrated area covered by the flap. Specimens consisting of the root apex and surrounding soft tissues were subjected to histopathological and histobacteriological analyses. Histobacteriological analysis revealed extensive resorptive defects on the root apices filled with thick bacterial biofilm, irregular detachment of the cementum layers with consequent infection of the underlying ...
Journal of endodontics, Mar 1, 2018
This histobacteriologic study described the pattern of intraradicular and extraradicular infectio... more This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses. The material comprised biopsy specimens from 24 (8 untreated and 16 treated) roots of teeth associated with apical periodontitis and a sinus tract. Specimens were obtained by periradicular surgery or extraction and were processed for histobacteriologic and histopathologic methods. Bacteria were found in the apical root canal system of all specimens, in the main root canal (22 teeth) and within ramifications (17 teeth). Four cases showed no extraradicular infection. Extraradicular bacteria occurred as a biofilm attached to the outer root surface in 17 teeth (5 untreated and 12 treated teeth), as actinomycotic colonies in 2 lesions, and as planktonic cells in 2 lesions. Extraradicular calculus formation (mineralized biofilm) was evident in 10 teeth. Teeth with chronic apical abscesses and sinus tracts showed a very complex infecti...
Endodontic Prognosis, 2016
Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, cariou... more Pulpal-periapical disease can be caused by carious infection or traumatic injury. However, carious infection is the primary etiology of pulpal and periapical disease. When caries involves the irritation dentin, the pulp becomes irreversibly inflamed. If untreated, the pulp will be infected and colonized by oral microbes. The infected pulp is not capable of self-healing because of lack of collateral circulation and restricted blood supply to effectively deliver innate and adaptive immune defense mechanisms. As pulp infection/inflammation spreads apically, periapical inflammation develops. Apical periodontitis is the extension of apical pulpitis. Usually, microbes from the infected canal would not establish infectious process in the periapical tissues, which have plenty of collateral circulation to deliver cellular and humoral defense components. When the pulp becomes infected, nonsurgical root canal therapy should be initiated as soon as possible to prevent the development of apical periodontitis. In teeth with infected pulp and apical periodontitis, the microbes have well-established infection in the canal system, form biofilm on the canal walls and isthmus, and have penetrated into the dentinal tubules and lateral/accessory canals. Therefore, it is difficult to eliminate the majority of microbes in the root canal system by chemomechanical debridement. Accordingly, teeth with irreversible pulpitis without apical periodontitis have a better prognosis than the teeth with apical periodontitis after nonsurgical root canal therapy. Understanding the pathogenesis of pulpal and periapical disease will guide the clinicians to take appropriate treatment procedures to achieve satisfactory wound healing of the disease.
Journal of Dentistry, 2017
Descriptions of the pathologic changes in the pulp and associated apical structures of human imma... more Descriptions of the pathologic changes in the pulp and associated apical structures of human immature teeth in response to deep caries are lacking in the literature. This article describes the histologic events associated with the radicular pulp and the apical tissues of human immature teeth following pulp inflammation and necrosis. Twelve immature teeth with destructive caries lesions were obtained from 8 patients. Two intact immature teeth served as controls. Teeth were extracted for reasons not related to this study and immediately processed for histopathologic and histobacteriologic analyses. Serial sections were examined for the pulp conditions and classified as reversible or irreversible pulp inflammation, or pulp necrosis. Other histologic parameters were also evaluated. In the 3 cases with reversible pulp inflammation, tissue in the pulp chamber showed mild to moderate inflammation and tertiary dentin formation related to tubules involved in the caries process. Overall, the radicular pulp tissue, apical papilla and Hertwig's epithelial root sheath (HERS) exhibited characteristics of normality. In the 3 cases with irreversible pulp inflammation, the pulps were exposed and severe inflammation occurred in the pulp chamber, with minor areas of necrosis and infection. Large areas of the canal walls were free from odontoblasts and lined by an atubular mineralized tissue. The apical papilla showed extremely reduced cellularity or lack of cells and HERS was discontinuous or absent. In the 6 cases with pulp necrosis, the coronal and radicular pulp tissue was necrotic and colonized by bacterial biofilms. The apical papilla could not be discerned, except for one case. HERS was absent in the necrotic cases. While immature teeth with reversible pulpitis showed histologic features almost similar to normal teeth in the canal and in the apical region, those with irreversible pulpitis and necrosis exhibited significant alterations not only in the radicular pulp but also in the apical tissues, including the apical papilla and HERS. Alterations in the radicular pulp and apical tissues help explain the outcome of current regenerative/reparative therapies and should be taken into account when devising more predictable therapeutic protocols for teeth with incomplete root formation.