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 Table of Contents  
Year : 2023  |  Volume : 15  |  Issue : 1  |  Page : 28-33

The prevalence of pulp stones in a North Indian population: A retrospective panoramic radiograph study

Department of Conservative Dentistry and Endodontics, Z.A. Dental College, AMU, Aligarh, Uttar Pradesh, India

Date of Submission10-Apr-2022
Date of Decision16-Aug-2022
Date of Acceptance17-Aug-2022
Date of Web Publication29-Dec-2022

Correspondence Address:
Sharique Alam
Department of Conservative Dentistry and Endodontics, Z.A. Dental College, AMU, Aligarh, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jorr.jorr_16_22

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Background: Pulp stones (PSs) are calcification within the pulp space formed as a physiologic or pathogenic response. Local and systemic factors are implicated in its occurrence.
Objectives: The aim of this study was to estimate the prevalence of PSs in a sample of the North Indian population using dental panoramic radiographs, and to report its association with age, gender, tooth class, dental arch, and restorative status of the teeth (restored/unrestored).
Materials and Methods: A total of 500 panoramic radiographs were randomly sampled from the archived dental records of patients treated in the dental hospital from 2015 to 2021. 450 panoramic radiographs containing 10,007 teeth met the inclusion criterion and were evaluated for the presence of PSs. The frequency of occurrence of PS between age, gender, tooth class, dental arch, and restorative status of the teeth was also calculated.
Results: PSs were detected in 128 (28.44%) out of the 450 patients, and 369 (3.68%) of the 10,007 teeth examined. A χ2 test of independence did not reveal any statistically significant association of PS with gender, age, and dental arch. The presence of PS was greatest in molars, and the results were statistically significant compared to all the other tooth types. The frequencies of PS were higher in the first molars (18.21%) than in the second molars (9.01%) when consolidated data for both arches were analyzed (P < 0.05). Carious/restored teeth displayed a statistically significant higher prevalence of PS than unrestored and intact teeth (12.95% vs. 10.32% prevalence rate as a ratio of total teeth examined).
Conclusions: The etiology of PSs is not completely validated. Further studies are needed to establish the factors involved in PS formation and evaluate its association with systemic diseases.

Keywords: Calcification, panoramic radiographs, prevalence, pulp stones

How to cite this article:
Lyngdoh D, Alam S, Iftekhar H, Rehman A, Nisar Andrabi SM. The prevalence of pulp stones in a North Indian population: A retrospective panoramic radiograph study. J Oral Res Rev 2023;15:28-33

How to cite this URL:
Lyngdoh D, Alam S, Iftekhar H, Rehman A, Nisar Andrabi SM. The prevalence of pulp stones in a North Indian population: A retrospective panoramic radiograph study. J Oral Res Rev [serial online] 2023 [cited 2023 May 30];15:28-33. Available from: https://www.jorr.org/text.asp?2023/15/1/28/365915

  Introduction Top

Pulp stones (PSs) are discrete calcification within the pulp tissue induced either as a physiological or a pathological response.[1] The PS in a tooth can number from 1 to 12 or even more and range in size from minute to substantially big particles that may obliterate the pulp space.[2] They are identified on a radiograph as a round or oval radiopaque structure and are more frequently encountered within the pulp chamber than in the radicular root canal space.[3] PS can occur “freely” within the pulp tissue or become “embedded,” or “adherent” to the dentinal wall. The presence of PS can have implications during endodontic treatment.[4] It may impair access to root canal orifices and constrain the biochemical shaping and disinfection of the root canal system.[4],[5]

PS, also known as denticles, are categorized as true denticles when composed of tubular dentine or as false denticles when calcification occurs around degenerated cells, thrombi, or collagen fibers.[4],[6] It is hypothesized that true denticles form when remnants of epithelial cells trapped within the pulp induce the mesenchymal stem cells to differentiate into odontoblasts. Unlike the true denticles, false denticles are associated with dystrophic calcification and form around a central nidus as a concentric or lamellar deposition.[7]

The exact cause of PS development is not known. However, they have been associated with several factors like aging, chronic irritants such as caries and deep restorations, orthodontic tooth movement, traumatic dental injury, and tooth transplantation.[4],[5] Systemic and genetic diseases such as dentine dysplasia, dentinogenesis imperfecta, Ehlers–Danlos syndrome, and Van der Woude syndrome have also been linked with an increased presence of PSs.[8],[9] A prevalence study conducted by Srivastava et al. on Saudi Arabian population found a higher risk of association of PSs (2.94 times) in patients with cardiovascular disease and diabetes mellitus (1.81 times) in comparison to healthy controls.[10] Studies have also associated PSs with other systemic diseases such as hypertension, renal diseases, and autoimmune diseases.

The prevalence of PSs documented in the literature ranges from 8% to 90%. Researchers have expressed the prevalence data as rates based either on the number of teeth or patients examined.[4] The studies have also utilized several radiographic techniques such as intraoral periapical (IOPA), Bitewing, orthopantograms (OPG), and cone-beam computed tomography to detect PSs. Analysis of an OPG allows clinicians to visualize and report the prevalence from the perspective of the complete dentition. In a study on Yemeni dental patients using digital panoramic radiographs, Kalaji et al. reported the prevalence as 18.6% for examined patients and 3.99% for the total teeth examined.[1] Kannan et al. evaluated 507 IOPA radiographs of 361 Malaysian dental patients and reported PSs in 162 individuals (44.9%) and 280 teeth (15.7%).[4] Bains et al. examined 500 bitewing radiographs of dental outpatients in the Punjab district of India and reported prevalence in patients as 41.8% and 9.09% in teeth.[11]

The definitive etiology for PS genesis is unclear though several etiological determinants have been suggested. Comprehending the causative and associated factors for PS formation can have clinical implications. The clinical importance of PS formation can range from its impact on endodontic treatment complexity to determining genetic and systemic disease risk factors. The current understanding suggests that PS formation may be a reactionary reparative response to chronic pulp irritation due to caries and restorative intervention.[5]

A dental literature review reveals limited prevalence and etiological association data of PSs in the Indian population. The aim of this study was to estimate the prevalence of PSs in a sample of the North Indian population and to determine the association of PSs with age, gender, tooth class, dental arch, and restorative status of the teeth (restored/unrestored).

  Materials and Methods Top

The present study was conducted as a retrospective study by evaluating the panoramic radiograph of patients treated in Dr. Z.A. Dental College, A.M.U., India. The study sample was collected by random allocation from the archived records of the patients treated between Jan 2015 to December 2021. The panoramic radiographs of the diagnostic quality of patients between 10 and 80 years were analyzed, which included 450 patients and 10,007 teeth. Panoramic radiographs demonstrating incomplete coverage of the maxillary or mandibular jaws, overlapped images of the teeth, anatomic superimposition or poor diagnostic quality images such as the presence of spine ghost shadow, and completely edentulous dental arches were excluded from the study. Primary teeth and unerupted, impacted, missing/extracted, or endodontically treated permanent teeth were excluded from the calculation of the prevalence of PSs. Two clinicians independently examined the panoramic radiographs using a dental X-ray viewer and a magnifying lens. A tooth was documented as having a PS if the pulpal space (within the pulp chamber or root canals or extending from the pulp chamber into the root canals) had an interceding radiopaque mass. The intraexaminer reliability was calculated by rescoring 5% (23 panoramic radiographs, 646 teeth). A 98% agreement was obtained, indicating a highly reliable intraexaminer scoring. Interexaminer reliability for detecting PSs on the panoramic radiographs was determined by calculating the kappa value. A high degree of interexaminer agreement was found with kappa values >0.9. Discordance among the clinicians in recording the PS status was resolved by mutual consensus. The information was documented in a Microsoft Excel spreadsheet prepared in accordance with the data parameters required for the study. The interrelationship between PSs and age, gender, tooth class, dental arch, and restorative status of the tooth (restored/unrestored) was analyzed using Chi-square test. The statistical significance level for data analysis was set at a 5% probability level. The Statistical Package for the Social Sciences (SPSS) software version 25 (IBM Corp.; Armonk, NY, USA) was utilized for data evaluation.

  Results Top

In the present study, 500 panoramic radiographs were initially evaluated. Fifty panoramic radiographs were excluded from assessment as they did not comply with the inclusion criterion or were of unacceptable diagnostic quality. 450 panoramic radiographs with the inclusion of 10,007 teeth were finally assessed for the presence of PSs.

Prevalence of pulp stones (as a ratio of subjects examined) and distribution between genders and age groups

PSs were detected in 128 (28.44%) out of the 450 patients examined. Among the 128 patients, 72 (27.48%) out of the 262 males and 56 (29.78%) out of the 188 females exhibited PSs [Table 1]. To investigate the relationship between gender and the presence of PSs, a Chi-square test of independence was used. There was no statistically significant relationship between these variables. χ2 (df1, n = 450) = 0.2861, P = 0.59, Not statistically significant at P < 0.05.
Table 1: Prevalence and association of pulp stones with gender

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The patient records were categorized into seven age groups, and the distribution of PSs recorded among these groups is shown in [Table 2]. Patients aged 31–40 years had the highest prevalence of PSs (34.78%). A Chi-square test of independence was performed to investigate the association between the age groups and the presence of PSs. The relation between these variables was not statistically significant. χ2 (df 6, n = 450) = 10.512, P = 0.1047, not statistically significant at P < 0.05.
Table 2: Prevalence of pulp stones with age

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Prevalence of pulp stones (as a ratio of teeth examined) and their distribution among tooth types

PSs were found in 369 (3.68%) of the 10,007 teeth studied [Table 3]. PSs were recorded in 352 (11.32%) of the 3109 molars and 17 (0.66%) of the 2541 premolars. The most common occurrence was in the maxillary first molar (19.7%), followed by the mandibular first molar (16.7%). Premolars in both arches had a relatively lower presence of PSs. No PSs were detected in the anterior teeth of both the arches.
Table 3: The prevalence and distribution of pulp stones by tooth type and dental arch

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A Chi-square test of independence was used to investigate the relationship between the tooth type and the presence of PSs. The presence of PSs was greatest in molars and the results were statistically significant when compared to premolars. χ2 (df1, n = 10,007) = 259.9, P < 0.001, significant at P < 0.05.When data for both arches were combined, the prevalence of PSs in the first molars (18.21%) was higher than in the second molars (9.01%) (P < 0.05) [Table 3].

Pulp stone occurrence and dental arches

The frequency distribution and percentages of PSs among the various tooth class and arches are shown in [Table 3]. The occurrence of PSs in the mandibular (3.41%) and the maxillary (3.95%) arch was almost equal. A Chi-square test of independence was used to assess the association between the dental arches and the presence of PSs. The relation between these parameters was statistically not significant. χ2 (df1, n = 10,007) = 2.074, P = 0.15, not statistically significant at P < 0.05.

Pulp stones and dental status

The prevalence of PSs in intact teeth was compared to teeth with caries, restorations or other deformity. Restored and/or carious molars had a higher occurrence of PSs (153 PSs/1181 teeth, 12.95% prevalence rate as ratio of total teeth examined) than in unrestored and intact molar teeth (199 PSs/1928 teeth, 10.32% prevalence rate as ratio of total teeth examined) [Table 4].
Table 4: Prevalence and distribution of pulp stone based on tooth status

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A Chi-square test of independence was used to evaluate the association between dental status (intact/unrestored teeth vs. restored/carious teeth) and the presence of PSs in posterior teeth (premolars and molars). A statistically significant higher association of PSs with restored/carious teeth was observed in this study. χ2 (df1, n = 5650) = 5.47, P = 0.02, significant at P < 0.05.

  Discussion Top

PS detection has been examined in histologic or radiographic studies. The radiographs underestimate the actual prevalence as they can only detect pulpal calcifications >200 μm, but it is the only tool that can be employed in clinical studies.[7],[12] Radiographic studies includes evaluation on IOPA, bitewing, and panoramic radiographs. Most prevalence studies on PSs have been performed using bitewing and IOPA radiographs. These radiographs offer clear and accurate images; however, the field of view is limited, and the complete dentition cannot be visualized. Panoramic radiographs offer the advantage that pulp calcifications in the entire dentition can be screened from a single image.[13] The occurrence and distribution of PSs among gender, age groups, tooth types, dental arches, and carious/restored teeth were examined in the current study using dental panoramic radiography.

The prevalence rates of PSs have been expressed in different ways in the literature. The two most commonly utilized ways describe prevalence rate as a unit of the: (1) patients examined and (2) the teeth assessed. In the present study, as the complete dentition could be visualized on the panoramic radiographs, the prevalence rates were calculated and expressed in both units.

We found 28.44% subject unit and 3.68% teeth unit prevalence of PSs in the present study. Authors have reported varying prevalence. Sreelakshmi et al.[14] examined 150 panoramic radiographs and reported a subject unit prevalence of 53% and a teeth unit prevalence of 6%. Turkal et al.[15] documented a 12.7% prevalence in the patients and 2.1% prevalence in the teeth assessed. Zainab and Najmeej[16] recorded a prevalence rate of 34.8% in the patients and 7.3% in the teeth examined. The difference in prevalence rates can be attributed to variations in the research methodology as well as to the heterogeneity in study population, such as ethnicity, dental habits, and oral care.

In the current study, females had a greater PS prevalence than males (29.78% vs. 27.28%); however, the difference was not statistically significant. Similar results were also reported by various studies,[3],[5],[17] while few other studies showed significant difference between genders.[4],[15],[18],[19] In this study, the presence of PSs was highest in the 31–40 years age group (34.78%) and lowest in the >70 years age group (0%). The absence of PSs in this age group may be explained by the fact that only six patients were >70 years old, and most of them did not have full dentition retention. The age group of highest prevalence in this study (31–40 years) also indicates that reasons in addition to aging related reactionary calcification are responsible for pulpal calcifications. Similar findings have been reported by Satheeshkumar et al.[2] and Sreelakshmi et al.[14]

In the present study, the occurrence of PSs is almost similar in the maxilla (3.95%) and the mandible (3.41%). Comparable results were reported by Arys et al.[20] and Moss-Salentijn and Klyvert.[21] However, Ranjitkar et al.[5] described a statistically significant association of PSs with the maxillary arch. Higher frequencies were noted in first molars, with a prevalence of 19.7% in the maxilla and 16.7% in the mandible. These results are consistent with earlier investigations.[3],[4],[5],[17],[18] However, the study by al-Hadi Hamasha and Darwazeh[3] recorded a greater distribution of PSs in the mandibular molars and does not concur with the results in the current investigation. In the present study, PSs were seldom found in the premolars, and the reason for this is unclear. Ranjitkar et al.[5] alluded to the high distribution of PSs in molars to its rich blood supply that may be conducive to precipitating calcifications. The higher prevalence in molars can also be explained by the fact that molars are the first teeth to erupt and endures the most occlusal stresses among the tooth types.

A higher presence of PSs was noted in nonintact teeth; presumably, due to the chronic pulpal irritation in carious and restored teeth. The pulp-dentinal complex may mount a defence response to caries and microleakage around restorations, leading to pulpal calcifications. In the current investigation, a statistically significant association between PS occurrence in caries/unrestored teeth was noted, which is consistent with the findings by Sener et al.[22] and Ranjitkar et al.[5] However, some studies have been unable to detect any conclusive link between the presence of pulp PSs and dental caries or restorative status.[23]

There is a lack of consensus about the cause of pulpal calcifications. Age, gender, underlying systemic illnesses, pulp irritation brought on by deep caries, and restorative procedures have all been linked to the development of pulpal calcifications.[2],[11] The systemic association of PSs as a risk factor for renal stones and cardiovascular disease has been assessed by various studies. However, the results from these studies are inconclusive in indicating PSs as a risk factor for systemic diseases.

According to the current clinical opinion, PSs have no significance other than the potential to present challenges during endodontic therapy, such as impeding canal location and negotiation. Such clinical difficulties may be eliminated by incorporating dental surgical operating microscope or loupes fitted with coaxial illumination in clinical practices. Piezoelectric, ultrasonic, and nickel–titanium rotary instruments are efficient tools to facilitate removal of pulp calcifications to enable negotiation of root canal orifices.

The etiology of PSs is still unclear. More research is needed to determine the etiological factors that contribute to PS formation. Association of PSs with increasing age may find utility in forensic odontology for age assessment and needs to be confirmed by prospective studies. The relation of PSs with systemic diseases is also currently disputable. Further studies may be conducted to conclusively approve/disapprove its association.

  Conclusions Top

The prevalence of PSs in the present study based on the total patients examined was 28.44% and 3.68% based on the total teeth examined. No significant association was observed in the prevalence of PSs with age, gender, and dental arch. The frequency of PS presence was significantly greater in molars and in teeth that were not intact (either restored or carious). More research is needed to establish the association, etiology, and systemic implications of PSs.

Ethical statement

The study was approved by the Institutional Ethics Committee of Jawaharlal Nehru Medical College, Aligarh with Approval No IECJNMC/640.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Kalaji MN, Habib AA, Alwessabi M. Radiographic assessment of the prevalence of pulp stones in a Yemeni population sample. Eur Endod J 2017;2:1-6.  Back to cited text no. 1
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Bains SK, Bhatia A, Singh HP, Biswal SS, Kanth S, Nalla S. Prevalence of coronal pulp stones and its relation with systemic disorders in northern Indian central Punjabi population. ISRN Dent 2014;2014:617590.  Back to cited text no. 11
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  [Table 1], [Table 2], [Table 3], [Table 4]


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