Pulpal and Periapical Lesions
Upon completing this chapter, the student will be able to:
1. Dene the key terms listed at the beginning of the chapter.
2. Discuss the following related to pulpal lesions:
identication of pulpal lesions.
of the pulp chamber and pulp canals, and state the
signicance of knowing how these normal structures
pulp denticles (or “pulp stones”) and pulpitis.
3. Discuss the following related to periapical lesions:
identication of periapical lesions.
of periapical cysts, periapical granulomas, periapical
abscesses, periapical condensing osteitis, residual cysts,
residual granulomas, internal resorption, and external
4. Discuss the three types of cemento-osseous dysplasias
(CODs), including how they appear on radiographic images
and where they generally appear in the oral cavity in
addition to what demographic group is usually aected by
cemento-osseous dysplasia (COD)
dentoalveolar abscess (dental abscess)
orid cemento-osseous dysplasia
focal cemento-osseous dysplasia
periapical cemento-osseous dysplasia
periapical condensing osteitis
pulp denticle (pulp stone)
residual periapical lesions
As shown in Chapter 19, the pulp chambers and pulp
canals of teeth are seen radiographically as radiolucent areas,
because they contain noncalcied material and are hence
less dense than the tooth structure that surrounds them
(Fig. 22.1). High-pulp horns and large-pulp chambers can
occur in all age groups, not just in young patients in whom
these ndings are characteristic. e normal size and shape
of the pulp chamber and canals change with age, in certain
developmental anomalies, and in response to local irritants.
e radiographic densities of pulp chambers and canals
dier because of size, position in the tooth, and radiographic
angulation, but not because of vitality. Gradual reduction in
the size and shape of the pulp chamber and canal is marked
by the deposition of secondary dentin at the walls of the
Dental images are integral in the identication and evalua-
tion of pulpal and periapical lesions. is chapter discusses
various pulpal and periapical lesions, focusing on their
radiographic appearance and discussing additional infor-
mation about their other signicant characteristics for the
e most commonly seen pathologic condition after caries
and periodontal disease is pulpal necrosis and subsequent
periapical bone lesions. In fact, most pulpal and periapical
lesions are the sequelae of caries, trauma, infrabony lesions,
and advanced periodontal disease.
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24922 Pulpal and Periapical LesionsEDUCATIONAL OBJECTIVESUpon completing this chapter, the student will be able to:1. Dene the key terms listed at the beginning of the chapter.2. Discuss the following related to pulpal lesions:• Discusstheroleofdentalradiographicimagesintheidentication of pulpal lesions.• Describethenormalradiographicanatomicfeaturesof the pulp chamber and pulp canals, and state the signicance of knowing how these normal structures appear radiographically.• Statetheappearanceandidentiablecharacteristicsofpulp denticles (or “pulp stones”) and pulpitis.3. Discuss the following related to periapical lesions:• Discusstheroleofdentalradiographicimagesintheidentication of periapical lesions.• Statetheappearanceandidentiablecharacteristicsof periapical cysts, periapical granulomas, periapical abscesses, periapical condensing osteitis, residual cysts, residual granulomas, internal resorption, and external resorption.4. Discuss the three types of cemento-osseous dysplasias (CODs), including how they appear on radiographic images and where they generally appear in the oral cavity in addition to what demographic group is usually aected by these conditions.KEY TERMScalcicationcemento-osseous dysplasia (COD)dentoalveolar abscess (dental abscess)external resorptionorid cemento-osseous dysplasia (FLCOD)focal cemento-osseous dysplasia (FCOD)internal resorptionperiapical cemento-osseous dysplasia (PCOD)periapical condensing osteitisperiapical cystperiapical granulomaperiapical lesionspulp calcicationpulp denticle (pulp stone)residual cystresidual granulomaresidual periapical lesionsroot resorptionsecondary dentinAnatomyAs shown in Chapter 19, the pulp chambers and pulp canals of teeth are seen radiographically as radiolucent areas, because they contain noncalcied material and are hence less dense than the tooth structure that surrounds them (Fig. 22.1). High-pulp horns and large-pulp chambers can occur in all age groups, not just in young patients in whom these ndings are characteristic. e normal size and shape of the pulp chamber and canals change with age, in certain developmental anomalies, and in response to local irritants. e radiographic densities of pulp chambers and canals dier because of size, position in the tooth, and radiographic angulation, but not because of vitality. Gradual reduction in the size and shape of the pulp chamber and canal is marked by the deposition of secondary dentin at the walls of the IntroductionDental images are integral in the identication and evalua-tion of pulpal and periapical lesions. is chapter discusses various pulpal and periapical lesions, focusing on their radiographic appearance and discussing additional infor-mation about their other signicant characteristics for the dental professional.Pulpal Lesionse most commonly seen pathologic condition after caries and periodontal disease is pulpal necrosis and subsequent periapical bone lesions. In fact, most pulpal and periapical lesions are the sequelae of caries, trauma, infrabony lesions, and advanced periodontal disease. 250 CHAPTER 22 Pulpal and Periapical LesionsBA• Figure 22.1 Normal pulp chambers in anterior (A) and posterior teeth (B). Note the different shapes and densities and the presence of a pulp denticle in the rst premolar. • Figure 22.2 Pulp chambers receded with age. Secondary dentin formation. • Figure 22.3 Secondary dentin formation in second molar (arrow) in response to caries and restoration. • Figure 22.4 Dentinogenesis imperfecta. Note the early calcication of the pulp chamber and canals. chamber and canals and the appearance on radiographs of a radiopacity to replace the radiolucent area (Fig. 22.2). Radiographically, secondary and regular dentin appear the same and can only be dierentiated by the changes in the shape of the chamber and canals that accompany aging. e formation of secondary dentin with the resulting obliteration or narrowing of the pulp chamber and canals can be caused by dierent types of irritants. e most common causes are deep caries, pulp capping, deep-seated restorations, attrition, abrasion, and a healed tooth fracture (Fig. 22.3). is decrease in pulp and root chamber size also can be seen in the developmental disturbances dentinogen-esis imperfecta and dentinal dysplasia (Fig. 22.4).Pulp CalcicationsRadiographic Appearance/CharacteristicsPulp denticles or pulp stones are calcications that appear as well-dened radiopacities within the pulp chamber (Fig. 22.5). A radiolucent line may be seen separating the stone from the pulpal wall and may give the appearance of a “free-oating” denticle, but it is actually attached to the oor or wall of the chamber. e stones, which are composed of either dentin or calcied salts, have the density and appear-ance of dentin. Other than blocking endodontic access, pulp calcications have no clinical signicance and do not cause pulp strangulation, as was once thought.PulpitisRadiographic Appearance/Characteristicsere are no radiographic signs of pulpitis in the pulp chamber. Normal, inamed, or necrotic pulp all appear the same, because their densities are the same. e only possible 251CHAPTER 22 Pulpal and Periapical Lesionsand alveolar bone (Fig. 22.8). Depending on certain factors, a cyst, granuloma, or dentoalveolar abscess may develop at this point. If the exudate reacts with some residual epithelial rests, then a periapical cyst will form. e strength and type of bacteria and the tissue resistance determine whether a granuloma or abscess will develop. It is almost impos-sible to dierentiate radiographically between a periapical granuloma and a periapical cyst (Figs. 22.9 and 22.10). radiographic ndings related to pulpitis are the causative factors, such as caries, pulp exposure, tooth fracture, previ-ous pulp capping, or deep restorations (Fig. 22.6). e pulps of teeth may appear to vary in radiographic density. is is not because of dierences in vitality, but because of the dierences in object density of the overlying tooth structure.Periapical LesionsPeriapical Pathologic ConditionsRadiographic Appearance/CharacteristicsPeriapical lesions are seen in the apical tissues surround-ing the tooth after the pulp has become necrotic. e periodontal membrane, lamina dura, and alveolar bone are the aected tissues. is necrosis, or degeneration of the pulp, may be a result of carious invasion of the pulp, tooth fracture, and physical or chemical trauma (Fig. 22.7). e exudate from the pulp rst spills into the periodontal ligament, causing a thickening that can be seen radiographi-cally. e pressure then causes resorption of the lamina dura • Figure 22.6 Pulpitis with no apical changes. The second premolar was acutely sensitive to thermal stimulation and found to be partially nonvital. • Figure 22.7 Fractured crowns of maxillary central incisors. Note the proximity of the fracture lines to the pulp chambers. • Figure 22.8 A, Thickened periodontal membrane and early apical bone change on maxillary rst bicuspid. B, Early apical bone resorption. • Figure 22.5 Pulp stones in lower incisors. 252 CHAPTER 22 Pulpal and Periapical Lesionsmandibular premolar and molar apices (Fig. 22.12). In almost all cases, the teeth are shown to be nonvital through pulp testing. Although the condition may be asymptomatic, it should be considered a radiopaque type of periapical pathologic condition and treated accordingly, with either root canal therapy or extraction.Residual Periapical LesionsRadiographic Appearance/CharacteristicsResidual periapical lesions are radiolucencies that appear in edentulous areas of either the maxilla or the mandible. ey represent pathologic areas that arose from teeth extracted in the area. If a granuloma or cyst that surrounds the apex of a nonvital tooth is not curetted out at the time of extraction, it may remain, grow, and destroy bone or move and possibly devitalize teeth. Such a lesion is considered either a residual cyst or residual granuloma (Figs. 22.13 and 22.14). Residual periapical lesions are quite common and are always considered in a diagnosis of an infrabony lesion.• Figure 22.9 Periapical granuloma. • Figure 22.10 Periapical cyst. • Figure 22.11 Dentoalveolar abscess. • Figure 22.12 Periapical condensing osteitis on mesial and distal roots of the rst molar. e dentoalveolar abscess (dental abscess) may cause root resorption and a more diuse radiolucency (Fig. 22.11). If present, a stulous tract leading from the abscess to the oral cavity is very dicult to see on radiographs because of its tortuous course through the bone. It would only be evident if the stulous tract and the central ray were in the same cross-sectional plane. Furthermore, clinical evidence of a dental abscess including pain, swelling, and exudate may be present.Periapical Condensing OsteitisRadiographic Appearance/CharacteristicsPeriapical condensing osteitis is recognized by the forma-tion of dense bone around the apex of a tooth in response to low-grade pulpal necrosis. is radiopaque asymptomatic condition is seen most often at, but is not limited to, the 253CHAPTER 22 Pulpal and Periapical LesionsExternal ResorptionRadiographic Appearance/Characteristicse cause of external resorption is also unknown. In this case (Fig. 22.20), the cells of the periodontal ligament resorb the cementum and dentin of the root or pulp chambers Root ResorptionRoot resorption can be caused by chronic periapical or periodontal infection, trauma, pressure from tumors or cysts, or rapid excessive orthodontic pressure, or it can be idiopathic (i.e., an unknown cause; Figs. 22.15 to 22.18). In a dierential diagnosis, it is important to distinguish between smooth (cysts, tumors) and rough (infection, trauma) root resorption.Internal ResorptionRadiographic Appearance/Characteristicse cause of the destructive process known as internal resorption (Fig. 22.19) is unknown. e pulpal tissue resorbs the dentin surrounding the pulp chamber or canal and eventually perforates to the periodontal ligament. e radiographic ndings of internal resorption are irregularities and widening of the usually smooth, tapered outline of the root chamber. In advanced cases, the irregular outline of the resorption can be seen perforating the root structures and reaching the periodontal ligament.• Figure 22.13 Residual cyst of the mandible. • Figure 22.14 Residual cyst of the left mandible seen on a portion of a panoramic lm. • Figure 22.15 Root resorption resulting from trauma. • Figure 22.16 Root resorption resulting from chronic periodontal infection. • Figure 22.17 Root resorption resulting from excessive and rapid orthodontic movement. 254 CHAPTER 22 Pulpal and Periapical LesionsRadiographic appearance/characteristics: PCOD (PCD) is a three-stage lesion that is asymptomatic and self-limiting and for which no treatment is indicated. It is found in the apical region of vital mandibular anterior (canine-to-canine) teeth and originates in the peri-odontal membrane of the tooth. In its rst stage, it is radiolucent and resembles periapical disease. e second stage is mixed (radiolucent and radiopaque), because the radiolucent lesion starts to calcify. In its third stage, it is totally radiopaque. Clinically, the teeth always test vital, and in all cases no treatment is indicated. PCOD (PCD) must be dierentiated from periapical pathologic conditions and condensing osteitis by vitality testing.2. Focal cemento-osseous dysplasia (FCOD) is a con-dition similar to PCOD but occurs in the posterior mandible, distal to the canines. It usually occurs as a single-site lesion.3. Florid cemento-osseous dysplasia (FLCOD) is also considered a type of COD but can occur in both maxilla and mandible and in multiple quadrants.to reach the pulp. Radiographically, teeth with external resorption have a round or oval radiolucency lateral to or superimposed over the pulp canal. If it is superimposed, the outline of the normal canal can be seen through the superimposition. If the radiolucency is lateral to the pulp canal, it can be seen leading from the periodontal ligament. It does not aect the pulp canal in its early stages; however, it perforates into the pulp canal and devitalizes the pulp tissue in its later stages.Cemento-Osseous DysplasiaCemento-osseous dysplasia (COD) is a condition of the jaws that is inherently a benign lesion. It arises from the broblasts of the periodontal ligaments.• Figure 22.19 Internal root resorption. • Figure 22.20 External root resorption in maxillary and mandibular anterior teeth. NOTEThese conditions frequently affect middle-aged African-American females but are certainly not limited to this demographic group.• Figure 22.18 Root resorption resulting from a malignant tumor. ere are three types of COD:1. Periapical cemento-osseous dysplasia (PCOD), which is also known as periapical cemental dysplasia (PCD; Fig. 22.21). 255CHAPTER 22 Pulpal and Periapical Lesions• Figure 22.21 A, First-stage periapical cemento-osseous dysplasia (COD) resembling periapical disease. B, Second-stage (mixed) radiolucent lesion starting to calcify. C, Third-stage radiopaque area surrounding the tooth apex. All teeth test vital in all stages. Chapter Summary• Identicationofdeviationsfromthenormalappearanceof the pulp chamber, pulp canal, and the surrounding periapical supportive structures is an important function of dental radiographic images.• Pulpalcalcications,suchaspulpstones(pulpdenticles),are recognized solely by radiographic examination. Clini-cal examination will not reveal calcications in the pulp of a tooth. Pulpitis itself cannot be seen radiographically; however, the causative factors of pulpal inammation, such as caries, can be seen on dental images.• edierentiationbetweenperiapicalcystsandgranu-lomas cannot be made radiographically. A dentoalveolar abscess appears dierently on radiographs than periapical cysts and granulomas, and clinical signs and symptoms of an abscess may also be present.• Periapicallesionsonradiographscanappearradiopaque,radiolucent, or they may have a combination of both radiopaque and radiolucent components and thus may be considered “mixed lesions.” ese periapical lesions include periapical condensing osteitis, residual cysts, residual granulomas, and the three types of CODs.• Externalandinternalresorptionsbothappearradiolucenton dental images, because they are resorptive processes that, although both radiolucent, are specically identi-ed by their radiographic characteristics and location on the teeth that they aect.Chapter Review QuestionsState whether the following pulpal and periapical lesions appear radiolucent (RL), radiopaque (RO), or “mixed” on dental radiographic images. If the lesion does not appear RL, RO, or “mixed” on radiographs, please classify it as not applicable (NA).1. PCOD stage 22. Periapical granuloma3. Periapical condensing osteitis4. Externalrootresorption5. PCOD stage 36. Periapical cyst7. Residual granuloma8. Pulpitis9. Dentoalveolar abscess10. Pulp denticles11. PCOD stage 112. Residual cyst 256 CHAPTER 22 Pulpal and Periapical LesionsCritical Thinking ExerciseA 50-year-old female African-American patient presents to a dental facility for a routine dental examination. e patient’s radiation history and risk factors for dental diseases are determined, and the appropriate radiographic prescrip-tion is advised. e patient does not have any clinical signs or symptoms of any dental-related issues in the mandibular anterior region. Upon viewing the radiographs that were respectively prescribed, the dental professional notices multiple radiolucent lesions in the periapical region of the mandibular central and lateral incisors. Discuss the steps that the dental professional would take in formulating a dierential and denitive diagnosis of these radiographic lesions. Please include the following in your discussion: a. Describe the lesions as being radiolucent (RL), radio-paque (RO), or “mixed.” b. Describe the location of the lesions. c. State the results of a clinical examination of this area. d. State whether there was evidence of caries in the area of concern. e. State the signicance of the “positive” vitality test on the four teeth involved. f. Present your conclusion based on the information given and your knowledge of pulpal and periapical lesions as seen on dental images.BibliographyIannucci JM, Howerton LJ: Dental radiography: Principles and tech-niques,ed5,StLouis,MO,2016,ElsevierSaunders.White SC, Pharoah MJ: Oral radiology: Principles and interpretation, ed 5, St Louis, MO, 2004, Mosby.White SC, Pharoah MJ: Oral radiology: Principles and interpretation, ed 7, St Louis, MO, 2013, Mosby.