The pulp polyp, also known as chronic hyperplastic pulpitis or proliferative pulpitis, is an uncommon and specific type of inflammatory hyperplasia that is associated with a nonvital tooth.
Pulpal diseases are broadly divided into reversible and irreversible pulpitis and are based on the ability of the inflamed dental pulp to return to a healthy state once the noxious stimulus has been removed. In the case of the pulp polyp, the disease process is irreversible. In contrast to most cases of irreversible pulpitis, the pulp polyp is usually an incidental finding that occasionally mimics reactive and neoplastic diseases of the gingiva and adjacent periodontium.
The pulp polyp is the result of both mechanical irritation and bacterial invasion into the pulp of a tooth that exhibits significant crown destruction due to trauma or caries. The mechanical causes that may stimulate this response include a tooth fracture with pulpal exposure or loss of a dental restoration. Usually, the entire dentinal roof is exposed with the crown of a carious tooth. The large exposure of pulpal tissue to the oral environment and bacterial invasion results in a chronic inflammatory response that stimulates an exuberant granulation tissue reaction.
The hyperplastic tissue reaction occurs because the young dental pulp has a rich blood supply and favorable immune response that is more resistant to bacterialinfection. Furthermore, because the tooth is open to the oral cavity, transudates and exudates from the inflamed pulpal tissue drain freely and do not accumulate within the restricted and rigid confines of the tooth. Tissue necrosis with destruction of the microcirculation that usually accompanies irreversible pulpitis does not occur in part because of this lack of significant intrapulpal pressure. In young teeth in which the apex of the root is open, the risk of pulpal necrosis secondary to venous congestion is decreased. The presence of a rich vascular network in the young pulpal tissue is an important protective mechanism against the inflammatory response that significantly decreases with age.
The possible role of a type 1 hypersensitivity reaction has been hypothesized because of an increased presence and concentration of immunoglobulin E (IgE), histamine, and interleukin-4 (IL-4) within the pulp polyps when compared with healthy pulpal tissues.
Pulp polyps are reportedly uncommon in the United States, and no epidemiologic studies specifically document the frequency of this entity. Although this lesion is reported to be uncommon with only isolated references in the literature, the true prevalence of this reactive pulpal disease is likely to be underestimated because it is a well-recognized sequela of extensive dental caries in children.
Pulp polyps are uncommon in countries with routine access to dental care, but they are encountered more frequently in developing countries. In a study of Vietnamese refugees who sought dental care, the prevalence of pulp polyps was 6%. This high number of cases is an indication of the severity of dental disease in this impoverished population. In a Brazilian clinical study of traumatized primary teeth, the occurrence of pulp polyps was 2.3% in young children.
Pulp polyps tend to be asymptomatic and are not associated with any significant morbidity or mortality except for gross caries destruction with premature tooth loss in many cases.
No racial predilection is recognized for this sequela of dental caries; however, it is more common in individuals of lower socioeconomic background who have limited access to dental care than in other people.
No sexual predilection has been documented for this oral lesion.
This pulpal disease occurs almost exclusively in children and young adults, and it can occur in both the primary dentition and the permanent dentition. When trauma is the causative factor in primary anterior teeth, most examples are observed in children aged 2 years or younger.
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Pulp polyps are usually asymptomatic.
Direct pressure during mastication may cause mild-to-moderate tenderness.
Localized bleeding may occur when the soft tissue is manipulated or traumatized.
Most lesions are associated with a history of a long-standing carious lesion, a fractured tooth due to trauma, or a combination or these 2 insults. Pulp polyps reach a maximum size within a couple of months and then remain static.
There are rare examples of incomplete removal of a natal tooth that results in the formation of a pulp polyp. Mobility of the tooth and sensitivity to percussion are usually absent.
Drainage of a purulent exudate is not a characteristic finding.
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A spongy, soft tissue nodule extrudes from the cavitated or fractured surface of a tooth.
The surface varies from pink and smooth to red and white and granular. Red and ulcerated lesions are vascular and bleed when manipulated.
Polyps typically enlarge to fill the entire cavitated area or pulpal chamber of the tooth.
Soft tissue may merge with the adjacent attached gingiva.
Polyps usually develop in carious primary molars and first permanent molars because, anatomically in young persons, these teeth have large pulp chambers. Less frequently, maxillary central incisors in both dentitions are affected.
A pulp polyp is a single lesion, but multiple teeth may be affected.
Teeth with open or incomplete apexification of the root apices are the most susceptible.
Extrusion of the opposing molar or tipping of the adjacent teeth with space loss may be observed when significant destruction of the crown occurs.
Causes of a pulp polyp include the following:
Carious tooth with significant loss of tooth structure
Loss of a dental restoration that results in pulpal exposure
Fractured tooth due to trauma with a pulpal exposure
Pulpal tissue with access to a good blood supply
Possible hormonal (estrogen and progesterone) influence
Possible hypersensitivity reaction
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Intraoral radiographs, in particular periapical and bite-wing film views, are needed to confirm this diagnosis and to determine the extent of tooth destruction and if the inflammatory lesion involves the surrounding alveolar bone.
Radiographic findings demonstrate a large coronal radiolucency that extends to the pulpal chamber with focal loss of tooth structure, while the root apices may be either open or closed.
Although no bony changes are usually observed, the surrounding alveolar bone may reveal either an incipient periapical radiolucency that is consistent with chronic apical periodontitis or a localized radiopacity that is referred to as focal sclerosing osteomyelitis (condensing osteitis). In addition, vertical alveolar bone height may be decreased surrounding the involved tooth, which is indicative of periodontitis.
Radiographic imaging is required to determine the most appropriate treatment for the involved tooth.
Diagnosis and determination of the most appropriate treatment options are based on adjunctive tests, including response to percussion, thermal stimuli, and electric pulp testing. In most cases, the results of these adjunctive tests are similar to those obtained for healthy teeth, which is in contrast to most teeth that exhibit irreversible pulpitis. The normal responses should not confuse the practitioner that the pulpal tissue is healthy and therefore requires only conservative treatment. In addition, these tests help to differentiate a true pulp polyp from hyperplastic gingivitis that is overlying a cavitation from a nonvital tooth.
Affected teeth and pulpal tissue are occasionally submitted for gross and histopathologic examination. This examination is most important when the pulp polyp is diagnosed in multiple teeth and when the cause for this uncommon pulpal response is not obvious at clinical examination.
Microscopic findings reveal a mass of granulation tissue protruding from the crown of a fractured or carious tooth that resembles a pyogenic granuloma. The fibrovascular stroma contains numerous small, delicate vascular channels and a prominent inflammatory infiltrate composed of primarily lymphocytes, plasma cells, and neutrophils. Although the surface may be ulcerated, it is covered by stratified squamous epithelium that resembles oral mucosa in approximately 50% of these inflammatory hyperplastic lesions. The source of this epithelium appears to be from the engraftment of desquamated oral epithelial cells or the migration of the epithelium from the adjacent gingival tissues. In more mature lesions that are covered with squamous epithelium, the granulation tissue is replaced by fibrous connective tissue with minimal inflammation and foci of dystrophic calcification.
Bacteria (primarily gram positive) are found on the surface of the polyp and within the carious lesion. In many cases, the histopathologic changes are limited to the coronal pulp tissue with the apical tissue exhibiting only mild vasodilation and minimal chronic inflammation.
Ultrastructural examination of nerve fibers associated with the pulp polyp exhibits variable findings within the same tooth, ranging from normal to moderate or severe degeneration of both myelinated nerve fibers and unmyelinated nerve fibers.
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Treatment of a pulp polyp in a permanent tooth includes either root canal therapy or extraction of the tooth.
The more conservative pulpotomy treatment has been successful in selected cases when only the coronal pulp is affected.
In immature teeth with incomplete root development, placement of an apical barrier and strengthening of the thin root with composite resin may be indicated prior to root canal treatment.
Pulp revascularization of an immature permanent tooth is another new treatment approach that results in the formation of vital pulpal tissue.
The tooth requires a full-coverage crown following endodontic therapy.
Prior to extensive restorative treatment, the risks and benefits of this treatment, including the long-term prognosis of the affected tooth in a young child, needs to be thoroughly explained.
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The affected tooth is extracted when primary teeth are involved or when minimal tooth structure in permanent teeth is available for restoration or the alveolar bone support is unfavorable.
A surgical crown lengthening procedure may be needed to prepare a tooth for a full-coverage crown.
Healing is uneventful in most cases.
Systemic medications are not recommended for the management of this lesion. Antibiotics are not prescribed for the treatment of the pulp polyp, despite a bacterial component. However, an antibiotic paste mixture is used within the canals of the infected tooth when the revascularization process is performed for the treatment of the nonvital tooth.
Further Outpatient Care
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Periodic dental examinations are recommended to monitor the success of the root canal therapy or to intercept problems associated with the premature loss of a tooth.
Orthodontic treatment may be needed to restore the occlusion.
If a tooth is extracted, either a dental implant or fixed dental prosthesis (bridge) is a treatment option to restore function and aesthetics.
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Space discrepancy from crown destruction or premature loss of a tooth may result in a crowded malocclusion, supereruption of an opposing tooth, or the impaction of a succedaneous tooth.
Without definitive treatment, some of these long-standing, nonvital teeth may progress to symptomatic disease, including periapical inflammatory disease and (rarely) cellulitis and osteomyelitis of the jaws.
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The prognosis is excellent. No risk for recurrence exists once definitive treatment has been rendered.
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Reinforce the importance of routine oral health care to prevent the development of deep carious lesions that may cause inflammatory pulpal disease and more serious sequelae.
For excellent patient education resources, visit eMedicineHealth's Oral Health Center. Also, see eMedicineHealth's patient education article Toothache.
Pulp polyps involving the primary, first, and second mandibular molars in a young child with extensive dental caries.
Picture 2. Pulp polyp involving the permanent second mandibular molar in a young adult with multiple carious teeth.
Fibrosed pyogenic granuloma of the mandibular gingiva that partially surrounds a carious molar with crown destruction. Reactive gingival lesions that extend into a large carious lesion of an adjacent tooth may resemble a pulp polyp.
Low-power photomicrograph of a pulp polyp demonstrating inflamed fibrovascular tissue that is lined by stratified squamous epithelium (hematoxylin and eosin, original magnification X40).
Intermediate-power photomicrograph of a pulp polyp with superficial bacteria and exogenous, pigmented material overlying the surface epithelium (hematoxylin and eosin, original magnification X100).
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